{"id":2816,"date":"2016-08-24T19:11:26","date_gmt":"2016-08-24T19:11:26","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/?post_type=chapter&#038;p=2816"},"modified":"2017-09-06T19:07:17","modified_gmt":"2017-09-06T19:07:17","slug":"lewis-acids-and-bases","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/chapter\/lewis-acids-and-bases\/","title":{"raw":"Lewis Acids and Bases","rendered":"Lewis Acids and Bases"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Objectives<\/h3>\r\n<ul>\r\n \t<li id=\"x-ck12-QWNpZHMgYW5kIEJhc2Vz-chapter\">Define Lewis acids and bases.<\/li>\r\n \t<li>Give examples of Lewis acids and bases.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<div class=\"textbox examples\">\r\n<h3><strong>The big picture gets bigger <\/strong><\/h3>\r\n<p id=\"x-ck12-YmU2YmRmNDdkNWFmMjgyODM2NTZlOGZjOGFkMTQxZGM.-cnz\">Ideas in science never stay static. One discovery builds on another. Our concepts of acids and bases have grown from the fundamental ideas of Arrhenius to Br\u00f8nsted-Lowry to Lewis. Each step adds to our understanding of the world around us and makes the \u201cbig picture\u201d even bigger.<\/p>\r\n<img class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19213233\/20140811155914330068.png\" alt=\"Illustration of the classifications of acids\" width=\"250\" \/>\r\n\r\n<\/div>\r\n<h2>Lewis Acids and Bases<\/h2>\r\n<p id=\"x-ck12-YjYwMTc3YTA3Y2I0ZmQ4NDIxMmZkMThjMGFmMGYxYTA.-nfu\">Gilbert Lewis (1875\u20131946) proposed a third theory of acids and bases that is even more general than either the Arrhenius or Br\u00f8nsted-Lowry theories. A <strong> Lewis acid <\/strong> is a substance that accepts a pair of electrons to form a covalent bond. A <strong> Lewis base <\/strong> is a substance that donates a pair of electrons to form a covalent bond. So, a Lewis acid-base reaction is represented by the transfer of a pair of electrons from a base to an acid. A hydrogen ion, which lacks any electrons, accepts a pair of electrons. It is an acid under both the Br\u00f8nsted-Lowry and Lewis definitions. Ammonia consists of a nitrogen atom as the central atom with a lone pair of electrons. The reaction between ammonia and the hydrogen ion can be depicted as shown in the <strong>Figure 1<\/strong>.<\/p>\r\n\r\n<div id=\"x-ck12-YmZkZDc0YmIzN2ViY2QwMGYxNWM3NzUwODcyYjNiMGU.-fwj\" class=\"x-ck12-img-postcard x-ck12-nofloat\">\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"500\"]<img id=\"x-ck12-OTgwNDUtMTM2NDg5NTA3OC0xLTYtNS41LjcuMg..\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19213234\/20140811155914476260.png\" alt=\"Ammonia is both a Bronsted base and a Lewis base\" width=\"500\" height=\"177\" longdesc=\"Reaction%20between%20ammonia%20and%20proton.\" \/> Figure 1.\u00a0Reaction between ammonia and proton.[\/caption]\r\n\r\n<\/div>\r\n<p id=\"x-ck12-Yjk1ZTYxM2QxNmVhOTJkMzUyYjMwYTBiMjUzNzkzNzQ.-ti5\">The lone pair on the nitrogen atom is transferred to the hydrogen ion, making the NH<sub>3 <\/sub> a Lewis base while the H <sup> + <\/sup> is a Lewis acid.<\/p>\r\n<p id=\"x-ck12-NjliOTI4MWM4ZDcxMDkwNjg0OTRmZTIzYjEzODIyZTY.-b0p\">Some reactions that do not qualify as acid-base reactions under the other definitions do so under only the Lewis definition. An example is the reaction of ammonia with boron trifluoride.<\/p>\r\n\r\n<div id=\"x-ck12-OGM0MjU5NGI1YjQ4ZTM0NTI2NmNkZjZhZDhjNmFhZTA.-07l\" class=\"x-ck12-img-postcard x-ck12-nofloat\">\r\n\r\n[caption id=\"\" align=\"alignnone\" width=\"500\"]<img id=\"x-ck12-OTgwNDUtMTM2NDg5NTE4OC00NC0xNy01LjUuNy4z\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19213235\/20140811155914754669.png\" alt=\"Boron trifluoride is a Lewis acid but not a Bronsted acid\" width=\"500\" height=\"139\" longdesc=\"Ammonia%20and%20boron%20trifluoride.\" \/> Figure 2.\u00a0Ammonia and boron trifluoride.[\/caption]\r\n\r\n<\/div>\r\n<p id=\"x-ck12-ZDFmYTlhZTY0MDJjN2VkNmRlZjRjZGVmYjU3MDA2ZGY.-4pb\">Boron trifluoride is the Lewis acid, while ammonia is again the Lewis base. As there is no hydrogen ion involved in this reaction, it qualifies as an acid-base reaction only under the Lewis definition. The <strong> Table <\/strong> below summarizes the three acid-base theories.<\/p>\r\n\r\n<table id=\"x-ck12-ZGQyOWExMGFmOWRhMmYyZDFlMGU3YzlmNmFiODg3NjQ.-heu\" class=\"x-ck12-nofloat\" border=\"1\"><caption>Acid-Base Definitions<\/caption>\r\n<tbody>\r\n<tr>\r\n<td><strong> Type <\/strong><\/td>\r\n<td><strong> Acid <\/strong><\/td>\r\n<td><strong> Base <\/strong><\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Arrhenius<\/td>\r\n<td>H <sup> + <\/sup> ions in solution<\/td>\r\n<td>OH <sup> \u2212 <\/sup> ions in solution<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Br\u00f8nsted-Lowry<\/td>\r\n<td>H <sup> + <\/sup> donor<\/td>\r\n<td>H <sup> + <\/sup> acceptor<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Lewis<\/td>\r\n<td>electron-pair acceptor<\/td>\r\n<td>electron-pair donor<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<div class=\"textbox key-takeaways\">\r\n<h3>Summary<\/h3>\r\n<ul id=\"x-ck12-ZWVkOTczNmM5MWFlMTgyOGRkMDJiZjM1M2EzYWUxZjk.-c6i\">\r\n \t<li>Lewis acids and bases are defined.<\/li>\r\n \t<li>Examples of Lewis acids and bases are given.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<div class=\"textbox exercises\">\r\n<h3>Review<\/h3>\r\n<ol id=\"x-ck12-Y2FiMjUwZGRjNDkyYzhmNmM0ZGZkYzBmYjA5MWYyYjM.-8sb\">\r\n \t<li>What is the difference between a Lewis acid or base and a Br\u00f8nsted Lowry acid or base?<\/li>\r\n \t<li>What is required to happen in Lewis acid-base reactions?<\/li>\r\n \t<li>Do all Lewis acid-base reactions involve protons?<\/li>\r\n<\/ol>\r\n<\/div>\r\n<h3 class=\"x-ck12-data-problem-set\">Glossary<\/h3>\r\n<div class=\"x-ck12-data-vocabulary\">\r\n<ul id=\"x-ck12-NTk1ODVmYzRiZGJhZDY3ODM4MDhlNTAyYmI5MTg0ZjE.-eke\">\r\n \t<li><strong> Lewis acid: <\/strong> A substance that accepts a pair of electrons to form a covalent bond.<\/li>\r\n \t<li><strong> Lewis base: <\/strong> A substance that donates a pair of electrons to form a covalent bond.<\/li>\r\n<\/ul>\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Objectives<\/h3>\n<ul>\n<li id=\"x-ck12-QWNpZHMgYW5kIEJhc2Vz-chapter\">Define Lewis acids and bases.<\/li>\n<li>Give examples of Lewis acids and bases.<\/li>\n<\/ul>\n<\/div>\n<div class=\"textbox examples\">\n<h3><strong>The big picture gets bigger <\/strong><\/h3>\n<p id=\"x-ck12-YmU2YmRmNDdkNWFmMjgyODM2NTZlOGZjOGFkMTQxZGM.-cnz\">Ideas in science never stay static. One discovery builds on another. Our concepts of acids and bases have grown from the fundamental ideas of Arrhenius to Br\u00f8nsted-Lowry to Lewis. Each step adds to our understanding of the world around us and makes the \u201cbig picture\u201d even bigger.<\/p>\n<p><img decoding=\"async\" class=\"aligncenter\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19213233\/20140811155914330068.png\" alt=\"Illustration of the classifications of acids\" width=\"250\" \/><\/p>\n<\/div>\n<h2>Lewis Acids and Bases<\/h2>\n<p id=\"x-ck12-YjYwMTc3YTA3Y2I0ZmQ4NDIxMmZkMThjMGFmMGYxYTA.-nfu\">Gilbert Lewis (1875\u20131946) proposed a third theory of acids and bases that is even more general than either the Arrhenius or Br\u00f8nsted-Lowry theories. A <strong> Lewis acid <\/strong> is a substance that accepts a pair of electrons to form a covalent bond. A <strong> Lewis base <\/strong> is a substance that donates a pair of electrons to form a covalent bond. So, a Lewis acid-base reaction is represented by the transfer of a pair of electrons from a base to an acid. A hydrogen ion, which lacks any electrons, accepts a pair of electrons. It is an acid under both the Br\u00f8nsted-Lowry and Lewis definitions. Ammonia consists of a nitrogen atom as the central atom with a lone pair of electrons. The reaction between ammonia and the hydrogen ion can be depicted as shown in the <strong>Figure 1<\/strong>.<\/p>\n<div id=\"x-ck12-YmZkZDc0YmIzN2ViY2QwMGYxNWM3NzUwODcyYjNiMGU.-fwj\" class=\"x-ck12-img-postcard x-ck12-nofloat\">\n<div style=\"width: 510px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" id=\"x-ck12-OTgwNDUtMTM2NDg5NTA3OC0xLTYtNS41LjcuMg..\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19213234\/20140811155914476260.png\" alt=\"Ammonia is both a Bronsted base and a Lewis base\" width=\"500\" height=\"177\" longdesc=\"Reaction%20between%20ammonia%20and%20proton.\" \/><\/p>\n<p class=\"wp-caption-text\">Figure 1.\u00a0Reaction between ammonia and proton.<\/p>\n<\/div>\n<\/div>\n<p id=\"x-ck12-Yjk1ZTYxM2QxNmVhOTJkMzUyYjMwYTBiMjUzNzkzNzQ.-ti5\">The lone pair on the nitrogen atom is transferred to the hydrogen ion, making the NH<sub>3 <\/sub> a Lewis base while the H <sup> + <\/sup> is a Lewis acid.<\/p>\n<p id=\"x-ck12-NjliOTI4MWM4ZDcxMDkwNjg0OTRmZTIzYjEzODIyZTY.-b0p\">Some reactions that do not qualify as acid-base reactions under the other definitions do so under only the Lewis definition. An example is the reaction of ammonia with boron trifluoride.<\/p>\n<div id=\"x-ck12-OGM0MjU5NGI1YjQ4ZTM0NTI2NmNkZjZhZDhjNmFhZTA.-07l\" class=\"x-ck12-img-postcard x-ck12-nofloat\">\n<div style=\"width: 510px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" id=\"x-ck12-OTgwNDUtMTM2NDg5NTE4OC00NC0xNy01LjUuNy4z\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/53\/2014\/08\/19213235\/20140811155914754669.png\" alt=\"Boron trifluoride is a Lewis acid but not a Bronsted acid\" width=\"500\" height=\"139\" longdesc=\"Ammonia%20and%20boron%20trifluoride.\" \/><\/p>\n<p class=\"wp-caption-text\">Figure 2.\u00a0Ammonia and boron trifluoride.<\/p>\n<\/div>\n<\/div>\n<p id=\"x-ck12-ZDFmYTlhZTY0MDJjN2VkNmRlZjRjZGVmYjU3MDA2ZGY.-4pb\">Boron trifluoride is the Lewis acid, while ammonia is again the Lewis base. As there is no hydrogen ion involved in this reaction, it qualifies as an acid-base reaction only under the Lewis definition. The <strong> Table <\/strong> below summarizes the three acid-base theories.<\/p>\n<table id=\"x-ck12-ZGQyOWExMGFmOWRhMmYyZDFlMGU3YzlmNmFiODg3NjQ.-heu\" class=\"x-ck12-nofloat\">\n<caption>Acid-Base Definitions<\/caption>\n<tbody>\n<tr>\n<td><strong> Type <\/strong><\/td>\n<td><strong> Acid <\/strong><\/td>\n<td><strong> Base <\/strong><\/td>\n<\/tr>\n<tr>\n<td>Arrhenius<\/td>\n<td>H <sup> + <\/sup> ions in solution<\/td>\n<td>OH <sup> \u2212 <\/sup> ions in solution<\/td>\n<\/tr>\n<tr>\n<td>Br\u00f8nsted-Lowry<\/td>\n<td>H <sup> + <\/sup> donor<\/td>\n<td>H <sup> + <\/sup> acceptor<\/td>\n<\/tr>\n<tr>\n<td>Lewis<\/td>\n<td>electron-pair acceptor<\/td>\n<td>electron-pair donor<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div class=\"textbox key-takeaways\">\n<h3>Summary<\/h3>\n<ul id=\"x-ck12-ZWVkOTczNmM5MWFlMTgyOGRkMDJiZjM1M2EzYWUxZjk.-c6i\">\n<li>Lewis acids and bases are defined.<\/li>\n<li>Examples of Lewis acids and bases are given.<\/li>\n<\/ul>\n<\/div>\n<div class=\"textbox exercises\">\n<h3>Review<\/h3>\n<ol id=\"x-ck12-Y2FiMjUwZGRjNDkyYzhmNmM0ZGZkYzBmYjA5MWYyYjM.-8sb\">\n<li>What is the difference between a Lewis acid or base and a Br\u00f8nsted Lowry acid or base?<\/li>\n<li>What is required to happen in Lewis acid-base reactions?<\/li>\n<li>Do all Lewis acid-base reactions involve protons?<\/li>\n<\/ol>\n<\/div>\n<h3 class=\"x-ck12-data-problem-set\">Glossary<\/h3>\n<div class=\"x-ck12-data-vocabulary\">\n<ul id=\"x-ck12-NTk1ODVmYzRiZGJhZDY3ODM4MDhlNTAyYmI5MTg0ZjE.-eke\">\n<li><strong> Lewis acid: <\/strong> A substance that accepts a pair of electrons to form a covalent bond.<\/li>\n<li><strong> Lewis base: <\/strong> A substance that donates a pair of electrons to form a covalent bond.<\/li>\n<\/ul>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-2816\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Chemistry Concepts Intermediate. <strong>Authored by<\/strong>: Calbreath, Baxter, et al.. <strong>Provided by<\/strong>: CK12.org. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/\">http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">CC BY-NC: Attribution-NonCommercial<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":4,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Chemistry Concepts Intermediate\",\"author\":\"Calbreath, Baxter, et al.\",\"organization\":\"CK12.org\",\"url\":\"http:\/\/www.ck12.org\/book\/CK-12-Chemistry-Concepts-Intermediate\/\",\"project\":\"\",\"license\":\"cc-by-nc\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-2816","chapter","type-chapter","status-publish","hentry"],"part":2342,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/2816","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":4,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/2816\/revisions"}],"predecessor-version":[{"id":3699,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/2816\/revisions\/3699"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/parts\/2342"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapters\/2816\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/media?parent=2816"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/pressbooks\/v2\/chapter-type?post=2816"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/contributor?post=2816"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/umes-cheminter\/wp-json\/wp\/v2\/license?post=2816"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}