{"id":6304,"date":"2017-09-10T03:53:08","date_gmt":"2017-09-10T03:53:08","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/?post_type=chapter&#038;p=6304"},"modified":"2017-10-30T18:27:01","modified_gmt":"2017-10-30T18:27:01","slug":"14-lewis-acids-and-bases","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/chapter\/14-lewis-acids-and-bases\/","title":{"raw":"14.2 Lewis Acids and Bases","rendered":"14.2 Lewis Acids and Bases"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Objectives<\/h3>\r\nBy the end of this module, you will be able to:\r\n<ul>\r\n \t<li>Identify acids and bases according to the Lewis definition<\/li>\r\n \t<li>Write equations for the formation of adducts<\/li>\r\n \t<li>Predict the products of a Lewis acid-base reaction<\/li>\r\n<\/ul>\r\n<\/div>\r\nIn 1923, G. N. <strong>Lewis<\/strong> proposed a generalized definition of acid-base behavior in which acids and bases are identified by their ability to accept or to donate a pair of electrons and form a coordinate covalent bond.\r\n\r\nA <strong>coordinate covalent bond<\/strong> (or dative bond) occurs when one of the atoms in the bond provides both bonding electrons. For example, a coordinate covalent bond occurs when a water molecule combines with a hydrogen ion to form a hydronium ion. A coordinate covalent bond also results when an ammonia molecule combines with a hydrogen ion to form an ammonium ion. Both of these equations are shown here.\r\n\r\n<img class=\"wp-image-4955 aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/08\/23214500\/CNX_Chem_15_03_hydronium_img.jpg\" alt=\"This figure shows two reactions represented with Lewis structures. The first shows an O atom bonded to two H atoms. The O atom has two lone pairs of electrons. There is a plus sign and then an H atom with a superscript positive sign followed by a right-facing arrow. The next Lewis structure is in brackets and shows an O atom bonded to three H atoms. There is one lone pair of electrons on the O atom. Outside of the brackets is a superscript positive sign. The second reaction shows an N atom bonded to three H atoms. The N atom has one lone pair of electrons. There is a plus sign and then an H superscript positive sign. After the H superscript positive sign is a right-facing arrow. The next Lewis structure is in brackets. It shows an N atom bonded to four H atoms. There is a superscript positive sign outside the brackets.\" width=\"880\" height=\"310\" \/>\r\n\r\nA <strong>Lewis acid<\/strong> is any species (molecule or ion) that can accept a pair of electrons, and a <strong>Lewis base<\/strong> is any species (molecule or ion) that can donate a pair of electrons.\r\n\r\nA Lewis acid-base reaction occurs when a base donates a pair of electrons to an acid. A <strong>Lewis acid-base adduct<\/strong>, a compound that contains a coordinate covalent bond between the Lewis acid and the Lewis base, is formed. The following equations illustrate the general application of the Lewis concept.\r\n\r\nThe boron atom in boron trifluoride, BF<sub>3<\/sub>, has only six electrons in its valence shell. Being short of the preferred octet, BF<sub>3<\/sub> is a very good Lewis acid and reacts with many Lewis bases; a fluoride ion is the Lewis base in this reaction, donating one of its lone pairs:\r\n\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214001\/CNX_Chem_15_02_BF3-LA_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left, an F atom is surrounded by four electron dot pairs and has a superscript negative symbol. This structure is labeled below as \u201cLewis base.\u201d Following a plus sign is another structure which has a B atom at the center and three F atoms single bonded above, right, and below. Each F atom has three pairs of electron dots. This structure is labeled below as \u201cLewis acid.\u201d Following a right pointing arrow is a structure in brackets that has a central B atom to which 4 F atoms are connected with single bonds above, below, to the left, and to the right. Each F atom in this structure has three pairs of electron dots. Outside the brackets is a superscript negative symbol. This structure is labeled below as \u201cAcid-base adduct.\u201d\" width=\"879\" height=\"334\" \/>\r\n\r\nIn the following reaction, each of two ammonia molecules, Lewis bases, donates a pair of electrons to a silver ion, the Lewis acid:\r\n\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214002\/CNX_Chem_15_02_NH3-LBase_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left side, a 2 preceeds an N atom which has H atoms single bonded above, to the left, and below. A single electron dot pair is on the right side of the N atom. This structure is labeled below as \u201cLewis base.\u201d Following a plus sign is an A g atom which has a superscript plus symbol. Following a right pointing arrow is a structure in brackets that has a central A g atom to which N atoms are connected with single bonds to the left and to the right. Each of these N atoms has H atoms bonded above, below, and to the outside of the structure. Outside the brackets is a superscript plus symbol. This structure is labeled below as \u201cAcid-base adduct.\u201d\" width=\"880\" height=\"223\" \/>\r\n\r\nNonmetal oxides act as Lewis acids and react with oxide ions, Lewis bases, to form oxyanions:\r\n\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214003\/CNX_Chem_15_02_NonmetalOx_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left, an O atom is surrounded by four electron dot pairs and has a superscript 2 negative. This structure is labeled below as \u201cLewis base.\u201d Following a plus sign is another structure which has an S atom at the center. O atoms are single bonded above and below. These O atoms have three electron dot pairs each. To the right of the S atom is a double bonded O atom which has two pairs of electron dots. This structure is labeled below as \u201cLewis acid.\u201d Following a right pointing arrow is a structure in brackets that has a central S atom to which 4 O atoms are connected with single bonds above, below, to the left, and to the right. Each of the O atoms has three pairs of electron dots. Outside the brackets is a superscript 2 negative. This structure is labeled below as \u201cAcid-base adduct.\u201d\" width=\"880\" height=\"223\" \/>\r\n\r\nMany Lewis acid-base reactions are displacement reactions in which one Lewis base displaces another Lewis base from an acid-base adduct, or in which one Lewis acid displaces another Lewis acid:\r\n\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214005\/CNX_Chem_15_02_Displace_img.jpg\" alt=\"This figure shows three chemical reactions in three rows using structural formulas. In the first row, to the left, in brackets is a structure that has a central A g atom to which N atoms are connected with single bonds to the left and to the right. Each of these N atoms has H atoms bonded above, below, and to the outside of the structure. Outside the brackets is a superscript plus symbol. This structure is labeled below as \u201cAcid-base adduct.\u201d Following a plus sign is a 2 and another structure in brackets that shows a C atom triple bonded to an N atom. The C atom has an unshared electron pair on its left side and the N atom has an unshared pair on its right side. Outside the brackets to the right is a superscript negative symbol. This structure is labeled below as \u201cBase.\u201d Following a right pointing arrow is a structure in brackets that has a central A g atom to which 4 FC atoms are connected with single bonds to the left and to the right. At each of the two ends, N atoms are triple bonded to the C atoms. The N atoms each have an unshared electron pair at the end of the structure. Outside the brackets is a superscript negative symbol. This structure is labeled below as \u201cNew adduct.\u201d Following a plus sign is an N atom which has H atoms single bonded above, to the left, and below. A single electron dot pair is on the left side of the N atom. This structure is labeled below as \u201cNew base.\u201d In the second row, on the left side in brackets is a structure with a central C atom. O atoms, each with three unshared electron pairs, are single bonded above and below and a third O atom, with two unshared electron pairs, is double bonded to the right. Outside the brackets is a superscript 2 negative. This structure is labeled below as \u201cAcid-base adduct.\u201d Following a plus sign is another structure which has an S atom at the center. O atoms are single bonded above and below. These O atoms have three electron dot pairs each. To the right of the S atom is a double bonded O atom which has two pairs of electron dots. This structure is labeled below as \u201cAcid.\u201d Following a right pointing arrow is a structure in brackets that has a central S atom to which 4 O atoms are connected with single bonds above, below, to the left, and to the right. Each of the O atoms has three pairs of electron dots. Outside the brackets is a superscript 2 negative. This structure is labeled below as \u201cNew adduct.\u201d\" width=\"880\" height=\"525\" \/>\r\n\r\nThe last displacement reaction shows how the reaction of a Br\u00f8nsted-Lowry acid with a base fits into the Lewis concept. A Br\u00f8nsted-Lowry acid such as HCl is an acid-base adduct according to the Lewis concept, and proton transfer occurs because a more stable acid-base adduct is formed. Thus, although the definitions of acids and bases in the two theories are quite different, the theories overlap considerably.\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Key Takeaways<\/h3>\r\nG.N. Lewis proposed a definition for acids and bases that relies on an atom\u2019s or molecule\u2019s ability to accept or donate electron pairs. A Lewis acid is a species that can accept an electron pair, whereas a Lewis base has an electron pair available for donation to a Lewis acid.\r\n\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Exercises<\/h3>\r\n<ol>\r\n \t<li>We have seen an introductory definition of an acid: An acid is a compound that reacts with water and increases the amount of hydronium ion present. In the chapter on acids and bases, we saw two more definitions of acids: a compound that donates a proton (a hydrogen ion, H<sup>+<\/sup>) to another compound is called a Br\u00f8nsted-Lowry acid, and a Lewis acid is any species that can accept a pair of electrons. Explain why the introductory definition is a macroscopic definition, while the Br\u00f8nsted-Lowry definition and the Lewis definition are microscopic definitions.<\/li>\r\n \t<li>Write the Lewis structures of the reactants and product of each of the following equations, and identify the Lewis acid and the Lewis base in each:\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>[latex]{\\text{CO}}_{2}+{\\text{OH}}^{-}\\longrightarrow {\\text{HCO}}_{3}{}^{-}[\/latex]<\/li>\r\n \t<li>[latex]\\text{B}{\\left(\\text{OH}\\right)}_{3}+{\\text{OH}}^{-}\\longrightarrow \\text{B}{\\left(\\text{OH}\\right)}_{4}{}^{-}[\/latex]<\/li>\r\n \t<li>[latex]{\\text{I}}^{-}+{\\text{I}}_{2}\\longrightarrow {\\text{I}}_{3}{}^{-}[\/latex]<\/li>\r\n \t<li>[latex]{\\text{AlCl}}_{3}+{\\text{Cl}}^{-}\\longrightarrow {\\text{AlCl}}_{4}{}^{-}[\/latex] (use Al-Cl single bonds)<\/li>\r\n \t<li>[latex]{\\text{O}}^{2-}+{\\text{SO}}_{3}\\longrightarrow {\\text{SO}}_{4}{}^{2-}[\/latex]<\/li>\r\n<\/ol>\r\n<\/li>\r\n \t<li>Write the Lewis structures of the reactants and product of each of the following equations, and identify the Lewis acid and the Lewis base in each:\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>[latex]{\\text{CS}}_{2}+{\\text{SH}}^{-}\\longrightarrow {\\text{HCS}}_{3}{}^{-}[\/latex]<\/li>\r\n \t<li>[latex]{\\text{BF}}_{3}+{\\text{F}}^{-}\\longrightarrow {\\text{BF}}_{4}{}^{-}[\/latex]<\/li>\r\n \t<li>[latex]{\\text{I}}^{-}+{\\text{SnI}}_{2}\\longrightarrow {\\text{SnI}}_{3}{}^{-}[\/latex]<\/li>\r\n \t<li>[latex]\\text{Al}{\\left(\\text{OH}\\right)}_{3}+{\\text{OH}}^{-}\\longrightarrow \\text{Al}{\\left(\\text{OH}\\right)}_{4}{}^{-}[\/latex]<\/li>\r\n \t<li>[latex]{\\text{F}}^{-}+{\\text{SO}}_{3}\\longrightarrow {\\text{SFO}}_{3}{}^{-}[\/latex]<\/li>\r\n<\/ol>\r\n<\/li>\r\n \t<li>Using Lewis structures, write balanced equations for the following reactions:\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>[latex]\\text{HCl}\\left(g\\right)+{\\text{PH}}_{3}\\left(g\\right)\\longrightarrow [\/latex]<\/li>\r\n \t<li>[latex]{\\text{H}}_{3}{\\text{O}}^{+}+{\\text{CH}}_{3}{}^{-}\\longrightarrow [\/latex]<\/li>\r\n \t<li>[latex]\\text{CaO}+{\\text{SO}}_{3}\\longrightarrow [\/latex]<\/li>\r\n \t<li>[latex]{\\text{NH}}_{4}{}^{+}+{\\text{C}}_{2}{\\text{H}}_{5}{\\text{O}}^{-}\\longrightarrow [\/latex]<\/li>\r\n<\/ol>\r\n<\/li>\r\n \t<li>In dilute aqueous solution HF acts as a weak acid. However, pure liquid HF (boiling point = 19.5 \u00b0C) is a strong acid. In liquid HF, HNO<sub>3<\/sub> acts like a base and accepts protons. The acidity of liquid HF can be increased by adding one of several inorganic fluorides that are Lewis acids and accept F<sup>\u2013<\/sup> ion (for example, BF<sub>3<\/sub> or SbF<sub>5<\/sub>). Write balanced chemical equations for the reaction of pure HNO<sub>3<\/sub> with pure HF and of pure HF with BF<sub>3<\/sub>. Write the Lewis structures of the reactants and products, and identify the conjugate acid-base pairs.<\/li>\r\n \t<li>The simplest amino acid is glycine, H<sub>2<\/sub>NCH<sub>2<\/sub>CO<sub>2<\/sub>H. The common feature of amino acids is that they contain the functional groups: an amine group, \u2013NH<sub>2<\/sub>, and a carboxylic acid group, \u2013CO<sub>2<\/sub>H. An amino acid can function as either an acid or a base. For glycine, the acid strength of the carboxyl group is about the same as that of acetic acid, CH<sub>3<\/sub>CO<sub>2<\/sub>H, and the base strength of the amino group is slightly greater than that of ammonia, NH<sub>3<\/sub>.\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>Write the Lewis structures of the ions that form when glycine is dissolved in 1 <em>M<\/em> HCl and in 1 <em>M<\/em> KOH.<\/li>\r\n \t<li>Write the Lewis structure of glycine when this amino acid is dissolved in water. (Hint: Consider the relative base strengths of the \u2013NH<sub>2<\/sub> and [latex]-{\\text{CO}}_{2}{}^{-}[\/latex] groups.)<\/li>\r\n<\/ol>\r\n<\/li>\r\n \t<li>Boric acid, H<sub>3<\/sub>BO<sub>3<\/sub>, is not a Br\u00f8nsted-Lowry acid but a Lewis acid.\r\n<ol style=\"list-style-type: lower-alpha\">\r\n \t<li>Write an equation for its reaction with water.<\/li>\r\n \t<li>Predict the shape of the anion thus formed.<\/li>\r\n \t<li>What is the hybridization on the boron consistent with the shape you have predicted?<\/li>\r\n<\/ol>\r\n<\/li>\r\n<\/ol>\r\n[reveal-answer q=\"246861\"]Show Selected Answers[\/reveal-answer]\r\n[hidden-answer a=\"246861\"]\r\n\r\n1.\r\n\r\n(a)\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214021\/CNX_Chem_15_02_Answer18a_img.jpg\" alt=\"This figure shows a chemical reaction modeled with structural formulas. On the left side is a structure with a central C atom. O atoms, each with two unshared electron pairs, are double bonded to the left and right sides of the C atom. Following a plus sign is another structure in brackets which has an O atom with three unshared electron dot pairs single bonded to an H atom on the right. Outside the brackets is superscript negative sign. Following a right pointing arrow is a structure in brackets that has a central C atom to which 3 O atoms are bonded. Above and slightly to the right, one of the O atoms is connected with a double bond. This O atom has two unshared electron pairs. The second O atom is single bonded below and slightly to the right. This O atom has three unshared electron pairs. The third O atom is bonded to the left of the C atom. This O atom has two unshared electron pairs and an H atom single bonded to its left. Outside the brackets to the right is a superscript negative symbol.\" width=\"650\" height=\"151\" \/>\r\n\r\n(b)\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214024\/CNX_Chem_15_02_Answer18b_img.jpg\" alt=\"This figure shows a chemical reaction modeled with structural formulas. On the left side is a structure that has a central B atom to which 3 O atoms are bonded. The O atoms above and below slightly right of the B atom each have an H atom single bonded to the right. The third O atom is single bonded to the left side of the B atom. This O atom has an H atom single bonded to its left side. All O atoms in this structure have two unshared electron pairs. Following a plus sign is another structure which has an O atom single bonded to an H atom on its right. The O atom has three unshared electron pairs. The structure appears in brackets with a superscript negative sign. Following a right pointing arrow is a structure in brackets has a central B atom to which 4 O atoms are bonded. The O atoms above, below, and right of the B atom each hav an H atom single bonded to the right. The third O atom is single bonded to the left side of the B atom. This O atom has an H atom single bonded to its left side. All O atoms in this structure have two unshared electron pairs. Outside the brackets to the right is a superscript negative symbol.\" width=\"879\" height=\"183\" \/>\r\n\r\n(c)\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214026\/CNX_Chem_15_02_Answer18c_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left, two I atoms, each with 3 unshared electron pairs, are joined with a single bond. Following a plus sign is another structure which has an I atom with four pairs of electron dots and a superscript negative sign. Following a right pointing arrow is a structure in brackets that has three I atoms connected in a line with single bonds. The two end I atoms have three unshared electron dot pairs and the I atom at the center has two unshared electron pairs. Outside the brackets is a superscript negative sign.\" width=\"650\" height=\"112\" \/>\r\n\r\n(d)\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214027\/CNX_Chem_15_02_Answer18d_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left, an A l atom is positioned at the center of a structure and three Cl atoms are single bonded above, leftt, and below. Each C l atom has three pairs of electron dots. Following a plus sign is another structure which has an F atom is surrounded by four electron dot pairs and a superscript negative symbol. Following a right pointing arrow is a structure in brackets that has a central A l atom to which 4 C l atoms are connected with single bonds above, below, to the left, and to the right. Each C l atom in this structure has three pairs of electron dots. Outside the brackets is a superscript negative symbol.\" width=\"650\" height=\"209\" \/>\r\n\r\n(e)\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214029\/CNX_Chem_15_02_Answer18e_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left is a structure which has an S atom at the center. O atoms are single bonded above and below. These O atoms have three electron dot pairs each. To the right of the S atom is a double bonded O atom which has two pairs of electron dots. Following a plus sign is an O atom which is surrounded by four electron dot pairs and has a superscript 2 negative. Following a right pointing arrow is a structure in brackets that has a central S atom to which 4 O atoms are connected with single bonds above, below, to the left, and to the right. Each of the O atoms has three pairs of electron dots. Outside the brackets is a superscript 2 negative.\" width=\"650\" height=\"207\" \/>\r\n\r\n4.\r\n\r\n(a)\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214037\/CNX_Chem_15_02_Answer24a_img.jpg\" alt=\"This figure represents a chemical reaction in two rows. The top row shows the reaction using chemical formulas. The second row uses structural formulas to represent the reaction. The first row contains the equation H C l ( g ) plus P H subscript 3 ( g ) right pointing arrow left bracket P H subscript 4 right bracket superscript plus plus left bracket C l with 4 pairs of electron dots right bracket superscript negative sign. The second row begins on the left with H left bracket C l with four unshared electron pairs right bracket plus a structure in brackets with a central P atom with H atoms single bonded at the left, above, and to the right. A single unshared electron pair is on the central P atom. Outside the brackets to the right is a superscript plus sign. Following a right pointing arrow is a structure in brackets with a central P atom with H atoms single bonded at the left, above, below, and to the right. Outside the brackets is a superscript plus sign. This structure is followed by a plus and a C l atom in brackets with four unshared electron pairs and a superscript negative sign.\" width=\"879\" height=\"274\" \/>\r\n\r\n(b) [latex]{\\text{H}}_{3}{\\text{O}}^{+}+{\\text{CH}}_{3}{}^{-}\\longrightarrow {\\text{CH}}_{4}+{\\text{H}}_{2}\\text{O}[\/latex]\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214039\/CNX_Chem_15_02_Answer24b_img.jpg\" alt=\"This figure represents a chemical reaction using structural formulas. A structure is shown in brackets on the left which is composed of a central O atom with one unshared electron pair and three single bonded H atoms to the left, right, and above the atom. Outside the brackets to the right is a superscript plus sign. Following a plus sign, is another structure in brackets composed of a central C atom with one unshared electron pair and three single bonded H atoms to the left, right, and above the atom. Outside the brackets to the right is a superscript negative sign. Following a right pointing arrow is a structure with a central C atom with H atoms single bonded above, below, left and right. Following a plus sign is a structure with a central O atom with two unshared electron pairs and two H atoms connected with single bonds.\" width=\"877\" height=\"114\" \/>\r\n\r\n(c) [latex]\\text{CaO}+{\\text{SO}}_{3}\\longrightarrow \\text{CaSO}4[\/latex]\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214040\/CNX_Chem_15_02_Answer24c_img.jpg\" alt=\"This figure represents a chemical reaction using structural formulas. On the left, C a superscript 2 plus is just left of bracket O with four unshared electron pairs right bracket superscript 2 negative plus a structure with a central S atom to which two O atoms are single bonded at the left and right, and a single O atom is double bonded above. The two single bonded O atoms each have three unshared electron pairs and the double bonded O atom has two unshared electron pairs. Following a right pointing arrow is C a superscript 2 plus just left of a structure in brackets with a central S atom which has 4 O atoms single bonded at the left, above, below, and to the right. Each of the O atoms has three unshared electron pairs. Outside the brackets to the right is a superscript two negative.\" width=\"879\" height=\"155\" \/>\r\n\r\n(d) [latex]{\\text{NH}}_{4}{}^{+}+{\\text{C}}_{2}{\\text{H}}_{5}{\\text{O}}^{-}\\longrightarrow {\\text{C}}_{2}{\\text{H}}_{5}\\text{OH}+{\\text{NH}}_{3}[\/latex]\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214042\/CNX_Chem_15_02_Answer24d_img.jpg\" alt=\"This figure represents a chemical reaction using structural formulas. A structure is shown in brackets on the left which is composed of a central N atom with four single bonded H atoms to the left, right, above, and below the atom. Outside the brackets to the right is a superscript plus sign. Following a plus sign, is another structure in brackets composed of a C atom with three single bonded H atoms above, below, and to the left. A second C atom is single bonded to the right. This C atom has H atoms single bonded above and below. To the right of the second C atom, an O atom is single bonded. This O atom has three unshared electron pairs. Outside the brackets to the right is a subperscript negative. Following a right pointing arrow is a structure composed of a C atom with three single bonded H atoms above, below, and to the left. A second C atom is single bonded to the right. This C atom has H atoms single bonded above and below. To the right of the second C atom, an O atom is single bonded. This O atom has two unshared electron pairs and an H atom single bonded to its right.\" width=\"885\" height=\"129\" \/>\r\n\r\n&nbsp;\r\n\r\n5. [latex]{\\text{HNO}}_{3}\\left(l\\right)+\\text{HF}\\left(l\\right)\\longrightarrow {\\text{H}}_{2}{\\text{NO}}_{3}{}^{+}+{\\text{F}}^{-}[\/latex]; [latex]\\text{HF}\\left(l\\right)+{\\text{BF}}_{3}\\left(g\\right)\\longrightarrow {\\text{H}}^{+}+{\\text{BF}}_{4}[\/latex]\r\n\r\n7. (a) [latex]{\\text{H}}_{3}{\\text{BO}}_{3}+{\\text{H}}_{2}\\text{O}\\longrightarrow {\\text{H}}_{4}{\\text{BO}}_{4}{}^{-}+{\\text{H}}^{+}[\/latex];\r\n\r\n(b) First, form a symmetrical structure with the unique atom, B, as the central atom. Then include the 32e<sup>\u2013<\/sup> to form the Lewis structure:\r\n\r\n<img class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214048\/CNX_Chem_15_02_Answer30b_img.jpg\" alt=\"An H atom is bonded to an O atom. The O atom has 2 dots above it and 2 dots below it. The O atom is bonded to a B atom, which has three additional O atoms bonded to it as well. Each of these additional O atoms has 4 dots arranged around it, and is bonded to an H atom. This entire molecule is contained in brackets, to the right of which is a superscripted negative sign.\" width=\"325\" height=\"176\" \/>\r\n\r\nBecause there are four bonds and no lone pair (unshared pair) on B, the electronic and molecular shapes are the same\u2014both tetrahedral.\r\n\r\n(c) The tetrahedral structure is consistent with <em>sp<\/em><sup>3<\/sup> hybridization.\r\n\r\n[\/hidden-answer]\r\n\r\n<\/div>\r\n<h2>Glossary<\/h2>\r\n&nbsp;\r\n\r\n<b>Lewis acid: <\/b>any species that can accept a pair of electrons and form a coordinate covalent bond\r\n\r\n<b>Lewis acid-base adduct: <\/b>compound or ion that contains a coordinate covalent bond between a Lewis acid and a Lewis base\r\n\r\n<b>Lewis base: <\/b>any species that can donate a pair of electrons and form a coordinate covalent bond","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Objectives<\/h3>\n<p>By the end of this module, you will be able to:<\/p>\n<ul>\n<li>Identify acids and bases according to the Lewis definition<\/li>\n<li>Write equations for the formation of adducts<\/li>\n<li>Predict the products of a Lewis acid-base reaction<\/li>\n<\/ul>\n<\/div>\n<p>In 1923, G. N. <strong>Lewis<\/strong> proposed a generalized definition of acid-base behavior in which acids and bases are identified by their ability to accept or to donate a pair of electrons and form a coordinate covalent bond.<\/p>\n<p>A <strong>coordinate covalent bond<\/strong> (or dative bond) occurs when one of the atoms in the bond provides both bonding electrons. For example, a coordinate covalent bond occurs when a water molecule combines with a hydrogen ion to form a hydronium ion. A coordinate covalent bond also results when an ammonia molecule combines with a hydrogen ion to form an ammonium ion. Both of these equations are shown here.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-4955 aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/08\/23214500\/CNX_Chem_15_03_hydronium_img.jpg\" alt=\"This figure shows two reactions represented with Lewis structures. The first shows an O atom bonded to two H atoms. The O atom has two lone pairs of electrons. There is a plus sign and then an H atom with a superscript positive sign followed by a right-facing arrow. The next Lewis structure is in brackets and shows an O atom bonded to three H atoms. There is one lone pair of electrons on the O atom. Outside of the brackets is a superscript positive sign. The second reaction shows an N atom bonded to three H atoms. The N atom has one lone pair of electrons. There is a plus sign and then an H superscript positive sign. After the H superscript positive sign is a right-facing arrow. The next Lewis structure is in brackets. It shows an N atom bonded to four H atoms. There is a superscript positive sign outside the brackets.\" width=\"880\" height=\"310\" \/><\/p>\n<p>A <strong>Lewis acid<\/strong> is any species (molecule or ion) that can accept a pair of electrons, and a <strong>Lewis base<\/strong> is any species (molecule or ion) that can donate a pair of electrons.<\/p>\n<p>A Lewis acid-base reaction occurs when a base donates a pair of electrons to an acid. A <strong>Lewis acid-base adduct<\/strong>, a compound that contains a coordinate covalent bond between the Lewis acid and the Lewis base, is formed. The following equations illustrate the general application of the Lewis concept.<\/p>\n<p>The boron atom in boron trifluoride, BF<sub>3<\/sub>, has only six electrons in its valence shell. Being short of the preferred octet, BF<sub>3<\/sub> is a very good Lewis acid and reacts with many Lewis bases; a fluoride ion is the Lewis base in this reaction, donating one of its lone pairs:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214001\/CNX_Chem_15_02_BF3-LA_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left, an F atom is surrounded by four electron dot pairs and has a superscript negative symbol. This structure is labeled below as \u201cLewis base.\u201d Following a plus sign is another structure which has a B atom at the center and three F atoms single bonded above, right, and below. Each F atom has three pairs of electron dots. This structure is labeled below as \u201cLewis acid.\u201d Following a right pointing arrow is a structure in brackets that has a central B atom to which 4 F atoms are connected with single bonds above, below, to the left, and to the right. Each F atom in this structure has three pairs of electron dots. Outside the brackets is a superscript negative symbol. This structure is labeled below as \u201cAcid-base adduct.\u201d\" width=\"879\" height=\"334\" \/><\/p>\n<p>In the following reaction, each of two ammonia molecules, Lewis bases, donates a pair of electrons to a silver ion, the Lewis acid:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214002\/CNX_Chem_15_02_NH3-LBase_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left side, a 2 preceeds an N atom which has H atoms single bonded above, to the left, and below. A single electron dot pair is on the right side of the N atom. This structure is labeled below as \u201cLewis base.\u201d Following a plus sign is an A g atom which has a superscript plus symbol. Following a right pointing arrow is a structure in brackets that has a central A g atom to which N atoms are connected with single bonds to the left and to the right. Each of these N atoms has H atoms bonded above, below, and to the outside of the structure. Outside the brackets is a superscript plus symbol. This structure is labeled below as \u201cAcid-base adduct.\u201d\" width=\"880\" height=\"223\" \/><\/p>\n<p>Nonmetal oxides act as Lewis acids and react with oxide ions, Lewis bases, to form oxyanions:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214003\/CNX_Chem_15_02_NonmetalOx_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left, an O atom is surrounded by four electron dot pairs and has a superscript 2 negative. This structure is labeled below as \u201cLewis base.\u201d Following a plus sign is another structure which has an S atom at the center. O atoms are single bonded above and below. These O atoms have three electron dot pairs each. To the right of the S atom is a double bonded O atom which has two pairs of electron dots. This structure is labeled below as \u201cLewis acid.\u201d Following a right pointing arrow is a structure in brackets that has a central S atom to which 4 O atoms are connected with single bonds above, below, to the left, and to the right. Each of the O atoms has three pairs of electron dots. Outside the brackets is a superscript 2 negative. This structure is labeled below as \u201cAcid-base adduct.\u201d\" width=\"880\" height=\"223\" \/><\/p>\n<p>Many Lewis acid-base reactions are displacement reactions in which one Lewis base displaces another Lewis base from an acid-base adduct, or in which one Lewis acid displaces another Lewis acid:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214005\/CNX_Chem_15_02_Displace_img.jpg\" alt=\"This figure shows three chemical reactions in three rows using structural formulas. In the first row, to the left, in brackets is a structure that has a central A g atom to which N atoms are connected with single bonds to the left and to the right. Each of these N atoms has H atoms bonded above, below, and to the outside of the structure. Outside the brackets is a superscript plus symbol. This structure is labeled below as \u201cAcid-base adduct.\u201d Following a plus sign is a 2 and another structure in brackets that shows a C atom triple bonded to an N atom. The C atom has an unshared electron pair on its left side and the N atom has an unshared pair on its right side. Outside the brackets to the right is a superscript negative symbol. This structure is labeled below as \u201cBase.\u201d Following a right pointing arrow is a structure in brackets that has a central A g atom to which 4 FC atoms are connected with single bonds to the left and to the right. At each of the two ends, N atoms are triple bonded to the C atoms. The N atoms each have an unshared electron pair at the end of the structure. Outside the brackets is a superscript negative symbol. This structure is labeled below as \u201cNew adduct.\u201d Following a plus sign is an N atom which has H atoms single bonded above, to the left, and below. A single electron dot pair is on the left side of the N atom. This structure is labeled below as \u201cNew base.\u201d In the second row, on the left side in brackets is a structure with a central C atom. O atoms, each with three unshared electron pairs, are single bonded above and below and a third O atom, with two unshared electron pairs, is double bonded to the right. Outside the brackets is a superscript 2 negative. This structure is labeled below as \u201cAcid-base adduct.\u201d Following a plus sign is another structure which has an S atom at the center. O atoms are single bonded above and below. These O atoms have three electron dot pairs each. To the right of the S atom is a double bonded O atom which has two pairs of electron dots. This structure is labeled below as \u201cAcid.\u201d Following a right pointing arrow is a structure in brackets that has a central S atom to which 4 O atoms are connected with single bonds above, below, to the left, and to the right. Each of the O atoms has three pairs of electron dots. Outside the brackets is a superscript 2 negative. This structure is labeled below as \u201cNew adduct.\u201d\" width=\"880\" height=\"525\" \/><\/p>\n<p>The last displacement reaction shows how the reaction of a Br\u00f8nsted-Lowry acid with a base fits into the Lewis concept. A Br\u00f8nsted-Lowry acid such as HCl is an acid-base adduct according to the Lewis concept, and proton transfer occurs because a more stable acid-base adduct is formed. Thus, although the definitions of acids and bases in the two theories are quite different, the theories overlap considerably.<\/p>\n<div class=\"textbox key-takeaways\">\n<h3>Key Takeaways<\/h3>\n<p>G.N. Lewis proposed a definition for acids and bases that relies on an atom\u2019s or molecule\u2019s ability to accept or donate electron pairs. A Lewis acid is a species that can accept an electron pair, whereas a Lewis base has an electron pair available for donation to a Lewis acid.<\/p>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Exercises<\/h3>\n<ol>\n<li>We have seen an introductory definition of an acid: An acid is a compound that reacts with water and increases the amount of hydronium ion present. In the chapter on acids and bases, we saw two more definitions of acids: a compound that donates a proton (a hydrogen ion, H<sup>+<\/sup>) to another compound is called a Br\u00f8nsted-Lowry acid, and a Lewis acid is any species that can accept a pair of electrons. Explain why the introductory definition is a macroscopic definition, while the Br\u00f8nsted-Lowry definition and the Lewis definition are microscopic definitions.<\/li>\n<li>Write the Lewis structures of the reactants and product of each of the following equations, and identify the Lewis acid and the Lewis base in each:\n<ol style=\"list-style-type: lower-alpha\">\n<li>[latex]{\\text{CO}}_{2}+{\\text{OH}}^{-}\\longrightarrow {\\text{HCO}}_{3}{}^{-}[\/latex]<\/li>\n<li>[latex]\\text{B}{\\left(\\text{OH}\\right)}_{3}+{\\text{OH}}^{-}\\longrightarrow \\text{B}{\\left(\\text{OH}\\right)}_{4}{}^{-}[\/latex]<\/li>\n<li>[latex]{\\text{I}}^{-}+{\\text{I}}_{2}\\longrightarrow {\\text{I}}_{3}{}^{-}[\/latex]<\/li>\n<li>[latex]{\\text{AlCl}}_{3}+{\\text{Cl}}^{-}\\longrightarrow {\\text{AlCl}}_{4}{}^{-}[\/latex] (use Al-Cl single bonds)<\/li>\n<li>[latex]{\\text{O}}^{2-}+{\\text{SO}}_{3}\\longrightarrow {\\text{SO}}_{4}{}^{2-}[\/latex]<\/li>\n<\/ol>\n<\/li>\n<li>Write the Lewis structures of the reactants and product of each of the following equations, and identify the Lewis acid and the Lewis base in each:\n<ol style=\"list-style-type: lower-alpha\">\n<li>[latex]{\\text{CS}}_{2}+{\\text{SH}}^{-}\\longrightarrow {\\text{HCS}}_{3}{}^{-}[\/latex]<\/li>\n<li>[latex]{\\text{BF}}_{3}+{\\text{F}}^{-}\\longrightarrow {\\text{BF}}_{4}{}^{-}[\/latex]<\/li>\n<li>[latex]{\\text{I}}^{-}+{\\text{SnI}}_{2}\\longrightarrow {\\text{SnI}}_{3}{}^{-}[\/latex]<\/li>\n<li>[latex]\\text{Al}{\\left(\\text{OH}\\right)}_{3}+{\\text{OH}}^{-}\\longrightarrow \\text{Al}{\\left(\\text{OH}\\right)}_{4}{}^{-}[\/latex]<\/li>\n<li>[latex]{\\text{F}}^{-}+{\\text{SO}}_{3}\\longrightarrow {\\text{SFO}}_{3}{}^{-}[\/latex]<\/li>\n<\/ol>\n<\/li>\n<li>Using Lewis structures, write balanced equations for the following reactions:\n<ol style=\"list-style-type: lower-alpha\">\n<li>[latex]\\text{HCl}\\left(g\\right)+{\\text{PH}}_{3}\\left(g\\right)\\longrightarrow[\/latex]<\/li>\n<li>[latex]{\\text{H}}_{3}{\\text{O}}^{+}+{\\text{CH}}_{3}{}^{-}\\longrightarrow[\/latex]<\/li>\n<li>[latex]\\text{CaO}+{\\text{SO}}_{3}\\longrightarrow[\/latex]<\/li>\n<li>[latex]{\\text{NH}}_{4}{}^{+}+{\\text{C}}_{2}{\\text{H}}_{5}{\\text{O}}^{-}\\longrightarrow[\/latex]<\/li>\n<\/ol>\n<\/li>\n<li>In dilute aqueous solution HF acts as a weak acid. However, pure liquid HF (boiling point = 19.5 \u00b0C) is a strong acid. In liquid HF, HNO<sub>3<\/sub> acts like a base and accepts protons. The acidity of liquid HF can be increased by adding one of several inorganic fluorides that are Lewis acids and accept F<sup>\u2013<\/sup> ion (for example, BF<sub>3<\/sub> or SbF<sub>5<\/sub>). Write balanced chemical equations for the reaction of pure HNO<sub>3<\/sub> with pure HF and of pure HF with BF<sub>3<\/sub>. Write the Lewis structures of the reactants and products, and identify the conjugate acid-base pairs.<\/li>\n<li>The simplest amino acid is glycine, H<sub>2<\/sub>NCH<sub>2<\/sub>CO<sub>2<\/sub>H. The common feature of amino acids is that they contain the functional groups: an amine group, \u2013NH<sub>2<\/sub>, and a carboxylic acid group, \u2013CO<sub>2<\/sub>H. An amino acid can function as either an acid or a base. For glycine, the acid strength of the carboxyl group is about the same as that of acetic acid, CH<sub>3<\/sub>CO<sub>2<\/sub>H, and the base strength of the amino group is slightly greater than that of ammonia, NH<sub>3<\/sub>.\n<ol style=\"list-style-type: lower-alpha\">\n<li>Write the Lewis structures of the ions that form when glycine is dissolved in 1 <em>M<\/em> HCl and in 1 <em>M<\/em> KOH.<\/li>\n<li>Write the Lewis structure of glycine when this amino acid is dissolved in water. (Hint: Consider the relative base strengths of the \u2013NH<sub>2<\/sub> and [latex]-{\\text{CO}}_{2}{}^{-}[\/latex] groups.)<\/li>\n<\/ol>\n<\/li>\n<li>Boric acid, H<sub>3<\/sub>BO<sub>3<\/sub>, is not a Br\u00f8nsted-Lowry acid but a Lewis acid.\n<ol style=\"list-style-type: lower-alpha\">\n<li>Write an equation for its reaction with water.<\/li>\n<li>Predict the shape of the anion thus formed.<\/li>\n<li>What is the hybridization on the boron consistent with the shape you have predicted?<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<div class=\"qa-wrapper\" style=\"display: block\"><span class=\"show-answer collapsed\" style=\"cursor: pointer\" data-target=\"q246861\">Show Selected Answers<\/span><\/p>\n<div id=\"q246861\" class=\"hidden-answer\" style=\"display: none\">\n<p>1.<\/p>\n<p>(a)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214021\/CNX_Chem_15_02_Answer18a_img.jpg\" alt=\"This figure shows a chemical reaction modeled with structural formulas. On the left side is a structure with a central C atom. O atoms, each with two unshared electron pairs, are double bonded to the left and right sides of the C atom. Following a plus sign is another structure in brackets which has an O atom with three unshared electron dot pairs single bonded to an H atom on the right. Outside the brackets is superscript negative sign. Following a right pointing arrow is a structure in brackets that has a central C atom to which 3 O atoms are bonded. Above and slightly to the right, one of the O atoms is connected with a double bond. This O atom has two unshared electron pairs. The second O atom is single bonded below and slightly to the right. This O atom has three unshared electron pairs. The third O atom is bonded to the left of the C atom. This O atom has two unshared electron pairs and an H atom single bonded to its left. Outside the brackets to the right is a superscript negative symbol.\" width=\"650\" height=\"151\" \/><\/p>\n<p>(b)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214024\/CNX_Chem_15_02_Answer18b_img.jpg\" alt=\"This figure shows a chemical reaction modeled with structural formulas. On the left side is a structure that has a central B atom to which 3 O atoms are bonded. The O atoms above and below slightly right of the B atom each have an H atom single bonded to the right. The third O atom is single bonded to the left side of the B atom. This O atom has an H atom single bonded to its left side. All O atoms in this structure have two unshared electron pairs. Following a plus sign is another structure which has an O atom single bonded to an H atom on its right. The O atom has three unshared electron pairs. The structure appears in brackets with a superscript negative sign. Following a right pointing arrow is a structure in brackets has a central B atom to which 4 O atoms are bonded. The O atoms above, below, and right of the B atom each hav an H atom single bonded to the right. The third O atom is single bonded to the left side of the B atom. This O atom has an H atom single bonded to its left side. All O atoms in this structure have two unshared electron pairs. Outside the brackets to the right is a superscript negative symbol.\" width=\"879\" height=\"183\" \/><\/p>\n<p>(c)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214026\/CNX_Chem_15_02_Answer18c_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left, two I atoms, each with 3 unshared electron pairs, are joined with a single bond. Following a plus sign is another structure which has an I atom with four pairs of electron dots and a superscript negative sign. Following a right pointing arrow is a structure in brackets that has three I atoms connected in a line with single bonds. The two end I atoms have three unshared electron dot pairs and the I atom at the center has two unshared electron pairs. Outside the brackets is a superscript negative sign.\" width=\"650\" height=\"112\" \/><\/p>\n<p>(d)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214027\/CNX_Chem_15_02_Answer18d_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left, an A l atom is positioned at the center of a structure and three Cl atoms are single bonded above, leftt, and below. Each C l atom has three pairs of electron dots. Following a plus sign is another structure which has an F atom is surrounded by four electron dot pairs and a superscript negative symbol. Following a right pointing arrow is a structure in brackets that has a central A l atom to which 4 C l atoms are connected with single bonds above, below, to the left, and to the right. Each C l atom in this structure has three pairs of electron dots. Outside the brackets is a superscript negative symbol.\" width=\"650\" height=\"209\" \/><\/p>\n<p>(e)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214029\/CNX_Chem_15_02_Answer18e_img.jpg\" alt=\"This figure illustrates a chemical reaction using structural formulas. On the left is a structure which has an S atom at the center. O atoms are single bonded above and below. These O atoms have three electron dot pairs each. To the right of the S atom is a double bonded O atom which has two pairs of electron dots. Following a plus sign is an O atom which is surrounded by four electron dot pairs and has a superscript 2 negative. Following a right pointing arrow is a structure in brackets that has a central S atom to which 4 O atoms are connected with single bonds above, below, to the left, and to the right. Each of the O atoms has three pairs of electron dots. Outside the brackets is a superscript 2 negative.\" width=\"650\" height=\"207\" \/><\/p>\n<p>4.<\/p>\n<p>(a)<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214037\/CNX_Chem_15_02_Answer24a_img.jpg\" alt=\"This figure represents a chemical reaction in two rows. The top row shows the reaction using chemical formulas. The second row uses structural formulas to represent the reaction. The first row contains the equation H C l ( g ) plus P H subscript 3 ( g ) right pointing arrow left bracket P H subscript 4 right bracket superscript plus plus left bracket C l with 4 pairs of electron dots right bracket superscript negative sign. The second row begins on the left with H left bracket C l with four unshared electron pairs right bracket plus a structure in brackets with a central P atom with H atoms single bonded at the left, above, and to the right. A single unshared electron pair is on the central P atom. Outside the brackets to the right is a superscript plus sign. Following a right pointing arrow is a structure in brackets with a central P atom with H atoms single bonded at the left, above, below, and to the right. Outside the brackets is a superscript plus sign. This structure is followed by a plus and a C l atom in brackets with four unshared electron pairs and a superscript negative sign.\" width=\"879\" height=\"274\" \/><\/p>\n<p>(b) [latex]{\\text{H}}_{3}{\\text{O}}^{+}+{\\text{CH}}_{3}{}^{-}\\longrightarrow {\\text{CH}}_{4}+{\\text{H}}_{2}\\text{O}[\/latex]<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214039\/CNX_Chem_15_02_Answer24b_img.jpg\" alt=\"This figure represents a chemical reaction using structural formulas. A structure is shown in brackets on the left which is composed of a central O atom with one unshared electron pair and three single bonded H atoms to the left, right, and above the atom. Outside the brackets to the right is a superscript plus sign. Following a plus sign, is another structure in brackets composed of a central C atom with one unshared electron pair and three single bonded H atoms to the left, right, and above the atom. Outside the brackets to the right is a superscript negative sign. Following a right pointing arrow is a structure with a central C atom with H atoms single bonded above, below, left and right. Following a plus sign is a structure with a central O atom with two unshared electron pairs and two H atoms connected with single bonds.\" width=\"877\" height=\"114\" \/><\/p>\n<p>(c) [latex]\\text{CaO}+{\\text{SO}}_{3}\\longrightarrow \\text{CaSO}4[\/latex]<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214040\/CNX_Chem_15_02_Answer24c_img.jpg\" alt=\"This figure represents a chemical reaction using structural formulas. On the left, C a superscript 2 plus is just left of bracket O with four unshared electron pairs right bracket superscript 2 negative plus a structure with a central S atom to which two O atoms are single bonded at the left and right, and a single O atom is double bonded above. The two single bonded O atoms each have three unshared electron pairs and the double bonded O atom has two unshared electron pairs. Following a right pointing arrow is C a superscript 2 plus just left of a structure in brackets with a central S atom which has 4 O atoms single bonded at the left, above, below, and to the right. Each of the O atoms has three unshared electron pairs. Outside the brackets to the right is a superscript two negative.\" width=\"879\" height=\"155\" \/><\/p>\n<p>(d) [latex]{\\text{NH}}_{4}{}^{+}+{\\text{C}}_{2}{\\text{H}}_{5}{\\text{O}}^{-}\\longrightarrow {\\text{C}}_{2}{\\text{H}}_{5}\\text{OH}+{\\text{NH}}_{3}[\/latex]<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214042\/CNX_Chem_15_02_Answer24d_img.jpg\" alt=\"This figure represents a chemical reaction using structural formulas. A structure is shown in brackets on the left which is composed of a central N atom with four single bonded H atoms to the left, right, above, and below the atom. Outside the brackets to the right is a superscript plus sign. Following a plus sign, is another structure in brackets composed of a C atom with three single bonded H atoms above, below, and to the left. A second C atom is single bonded to the right. This C atom has H atoms single bonded above and below. To the right of the second C atom, an O atom is single bonded. This O atom has three unshared electron pairs. Outside the brackets to the right is a subperscript negative. Following a right pointing arrow is a structure composed of a C atom with three single bonded H atoms above, below, and to the left. A second C atom is single bonded to the right. This C atom has H atoms single bonded above and below. To the right of the second C atom, an O atom is single bonded. This O atom has two unshared electron pairs and an H atom single bonded to its right.\" width=\"885\" height=\"129\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>5. [latex]{\\text{HNO}}_{3}\\left(l\\right)+\\text{HF}\\left(l\\right)\\longrightarrow {\\text{H}}_{2}{\\text{NO}}_{3}{}^{+}+{\\text{F}}^{-}[\/latex]; [latex]\\text{HF}\\left(l\\right)+{\\text{BF}}_{3}\\left(g\\right)\\longrightarrow {\\text{H}}^{+}+{\\text{BF}}_{4}[\/latex]<\/p>\n<p>7. (a) [latex]{\\text{H}}_{3}{\\text{BO}}_{3}+{\\text{H}}_{2}\\text{O}\\longrightarrow {\\text{H}}_{4}{\\text{BO}}_{4}{}^{-}+{\\text{H}}^{+}[\/latex];<\/p>\n<p>(b) First, form a symmetrical structure with the unique atom, B, as the central atom. Then include the 32e<sup>\u2013<\/sup> to form the Lewis structure:<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/887\/2015\/05\/23214048\/CNX_Chem_15_02_Answer30b_img.jpg\" alt=\"An H atom is bonded to an O atom. The O atom has 2 dots above it and 2 dots below it. The O atom is bonded to a B atom, which has three additional O atoms bonded to it as well. Each of these additional O atoms has 4 dots arranged around it, and is bonded to an H atom. This entire molecule is contained in brackets, to the right of which is a superscripted negative sign.\" width=\"325\" height=\"176\" \/><\/p>\n<p>Because there are four bonds and no lone pair (unshared pair) on B, the electronic and molecular shapes are the same\u2014both tetrahedral.<\/p>\n<p>(c) The tetrahedral structure is consistent with <em>sp<\/em><sup>3<\/sup> hybridization.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<h2>Glossary<\/h2>\n<p>&nbsp;<\/p>\n<p><b>Lewis acid: <\/b>any species that can accept a pair of electrons and form a coordinate covalent bond<\/p>\n<p><b>Lewis acid-base adduct: <\/b>compound or ion that contains a coordinate covalent bond between a Lewis acid and a Lewis base<\/p>\n<p><b>Lewis base: <\/b>any species that can donate a pair of electrons and form a coordinate covalent bond<\/p>\n","protected":false},"author":6181,"menu_order":3,"template":"","meta":{"_candela_citation":"[]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-6304","chapter","type-chapter","status-publish","hentry"],"part":2988,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/pressbooks\/v2\/chapters\/6304","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/wp\/v2\/users\/6181"}],"version-history":[{"count":8,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/pressbooks\/v2\/chapters\/6304\/revisions"}],"predecessor-version":[{"id":6499,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/pressbooks\/v2\/chapters\/6304\/revisions\/6499"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/pressbooks\/v2\/parts\/2988"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/pressbooks\/v2\/chapters\/6304\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/wp\/v2\/media?parent=6304"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/pressbooks\/v2\/chapter-type?post=6304"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/wp\/v2\/contributor?post=6304"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-mcc-chemistryformajors-2\/wp-json\/wp\/v2\/license?post=6304"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}