{"id":128,"date":"2021-06-29T17:12:41","date_gmt":"2021-06-29T17:12:41","guid":{"rendered":"https:\/\/sites.tntech.edu\/dcashman\/?p=128"},"modified":"2021-10-25T13:42:05","modified_gmt":"2021-10-25T13:42:05","slug":"catalytic-decomposition-of-hydrogen-peroxide-elephants-toothpaste","status":"publish","type":"post","link":"https:\/\/sites.tntech.edu\/dcashman\/2021\/06\/29\/catalytic-decomposition-of-hydrogen-peroxide-elephants-toothpaste\/","title":{"rendered":"Chemistry Demonstration: Catalytic Decomposition of Hydrogen Peroxide (Elephant&#8217;s Toothpaste)"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\"><strong>Introduction<\/strong><\/h3>\n\n\n\n<p>Hydrogen peroxide (H<sub>2<\/sub>O<sub>2<\/sub>) naturally decomposes to produce oxygen and water. However, this process takes a very long time. It may be sped up by the addition of a catalyst. In this experiment, we will use the iodide ion (I<sup>&#8211;<\/sup>) present in potassium iodide or sodium iodide as a catalyst to speed up the decomposition of hydrogen peroxide. The reaction is also exothermic, meaning that it releases heat.<\/p>\n\n\n\n<p>The catalyzed reactions are shown below:<\/p>\n\n\n\n<p>H<sub>2<\/sub>O<sub>2 (aq)<\/sub>&nbsp;+ I<sup>&#8211;<\/sup><sub>(aq)<\/sub>&nbsp;&#8211;&gt; H<sub>2<\/sub>O<sub>(l)<\/sub>&nbsp;+ IO<sup>&#8211;<\/sup><sub>(aq)<\/sub><\/p>\n\n\n\n<p>IO<sup>&#8211;<\/sup><sub>(aq)<\/sub>&nbsp;+ H<sub>2<\/sub>O<sub>2 (aq)<\/sub>&nbsp;&#8211;&gt; H<sub>2<\/sub>O<sub>(l)<\/sub>&nbsp;+ O<sub>2 (g)<\/sub><\/p>\n\n\n\n<p>The overall reaction is as follows:<\/p>\n\n\n\n<p>2 H<sub>2<\/sub>O<sub>2 (aq)<\/sub>&nbsp;&#8211;&gt; 2 H<sub>2<\/sub>O<sub>(l)<\/sub>&nbsp;+ O<sub>2 (g)<\/sub><\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Materials<\/strong><\/h3>\n\n\n\n<ul class=\"wp-block-list\"><li>30% Hydrogen Peroxide (H<sub>2<\/sub>O<sub>2<\/sub>)<\/li><li>Potassium iodide or Sodium iodide<\/li><li>Food Coloring<\/li><li>Liquid dish detergent (Palmolive)<\/li><li>1 Liter Graduated Cylinder<\/li><li>A large basin or tarp to facilitate cleanup<\/li><li>glowing splint (optional)<\/li><\/ul>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Procedure<\/strong><\/h3>\n\n\n\n<ol class=\"wp-block-list\"><li>Place the 1 Liter graduated cylinder in the center of the large basin or tarp.<\/li><li>Pour 50 mL of 30% hydrogen peroxide into the graduated cylinder. Add two to four drops of food coloring. Add a small layer of liquid dish detergent to the mixture.<\/li><li>Prepare a saturated solution of potassium iodide or sodium iodide by adding an excess of salt to deionized water. The supernate of these solutions is used to carry out the reaction.<\/li><li>Swirl the contents of the cylinder and quickly add 5 mL of saturated potassium iodide solution before the agitation has subsided. This reaction occurs rapidly, so stand back immediately after adding the potassium or sodium iodide solution.<\/li><li>The reaction produces water and oxygen gas. The oxygen gas is trapped in the foam bubbles of the soap solution. To test for the presence of oxygen, you can introduce a glowing splint to the graduated cylinder.<\/li><\/ol>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Safety<\/strong><\/h3>\n\n\n\n<p>This experiment utilizes 30% hydrogen peroxide, which is a strong oxidizing agent (household hydrogen peroxide is typically about 3%). Concentrated hydrogen peroxide can cause burns. Wear latex gloves, safety glasses, and avoid contact with the skin and mucous membranes.<\/p>\n\n\n\n<p>A safer version of this demonstration that utilizes 3% (household) hydrogen peroxide instead of 30% hyrogen peroxide is also available. See reference #2 below.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">Disposal of Waste Products<\/h4>\n\n\n\n<p>All waste products may be safely disposed of down the drain upon addition of plenty of water.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>References<\/strong><\/h3>\n\n\n\n<ol class=\"wp-block-list\"><li>Conklin, A.R.; Kessinger, A.&nbsp;<a href=\"http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/ed073p838%20target=\">Demonstration of the catalytic decomposition of hydrogen peroxide<\/a>.&nbsp;<em>J. Chem. Educ.<\/em>,&nbsp;<strong>1996<\/strong>, 73(9), 838.<\/li><li>Trujillo, C.A.&nbsp;<a href=\"http:\/\/pubs.acs.org\/doi\/abs\/10.1021\/ed082p855\" target=\"_blank\" rel=\"noreferrer noopener\">A modified demonstration of the catalytic decomposition of hydrogen peroxide<\/a>.&nbsp;<em>J. Chem. Educ.<\/em>,&nbsp;<strong>2005<\/strong>, 82(6), 855.<\/li><\/ol>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Introduction Hydrogen peroxide (H2O2) naturally decomposes to produce oxygen and water. However, this process takes a very long time. It may be sped up by the addition of a catalyst. In this experiment, we will use the iodide ion (I&#8211;) &hellip; <a href=\"https:\/\/sites.tntech.edu\/dcashman\/2021\/06\/29\/catalytic-decomposition-of-hydrogen-peroxide-elephants-toothpaste\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":155,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6,1],"tags":[],"class_list":["post-128","post","type-post","status-publish","format-standard","hentry","category-demos","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/posts\/128","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/users\/155"}],"replies":[{"embeddable":true,"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/comments?post=128"}],"version-history":[{"count":2,"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/posts\/128\/revisions"}],"predecessor-version":[{"id":145,"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/posts\/128\/revisions\/145"}],"wp:attachment":[{"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/media?parent=128"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/categories?post=128"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/sites.tntech.edu\/dcashman\/wp-json\/wp\/v2\/tags?post=128"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}