{"id":250784,"date":"2025-07-10T12:17:46","date_gmt":"2025-07-10T12:17:46","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=250784"},"modified":"2025-07-10T12:17:49","modified_gmt":"2025-07-10T12:17:49","slug":"the-following-mechanism-is-proposed","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/10\/the-following-mechanism-is-proposed\/","title":{"rendered":"The following mechanism is proposed"},"content":{"rendered":"\n<p>For the reaction 2H2O2 + 2HI -> 2H2O + I2, the following mechanism is proposed: 1. H2O2 + HI -> H2O + HOI 2. HOI -> H2O + I2 3. H2O2 + I2 -> 2H2O + O2 Derive an expression for the rate of formation of I2 using the steady-state approximation.<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>To derive an expression for the rate of formation of I2I_2I2\u200b in the given reaction using the steady-state approximation, let&#8217;s first break down the reaction and its proposed mechanism.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Given Reaction:<\/h3>\n\n\n\n<p>2H2O2+2HI\u21922H2O+I22H_2O_2 + 2HI \\rightarrow 2H_2O + I_22H2\u200bO2\u200b+2HI\u21922H2\u200bO+I2\u200b<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Proposed Mechanism:<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li>H2O2+HI\u2192H2O+HOIH_2O_2 + HI \\rightarrow H_2O + HOIH2\u200bO2\u200b+HI\u2192H2\u200bO+HOI (Step 1)<\/li>\n\n\n\n<li>HOI\u2192H2O+I2HOI \\rightarrow H_2O + I_2HOI\u2192H2\u200bO+I2\u200b (Step 2)<\/li>\n\n\n\n<li>H2O2+I2\u21922H2O+O2H_2O_2 + I_2 \\rightarrow 2H_2O + O_2H2\u200bO2\u200b+I2\u200b\u21922H2\u200bO+O2\u200b (Step 3)<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\">Step-by-Step Approach Using the Steady-State Approximation:<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Steady-State Approximation<\/strong>:<br>The steady-state approximation assumes that the concentration of intermediates (in this case, HOIHOIHOI and I2I_2I2\u200b) remains approximately constant throughout the reaction. This means that the rate of formation of these intermediates equals the rate of their consumption.<\/li>\n\n\n\n<li><strong>Rate of Formation and Consumption of HOIHOIHOI<\/strong>:<br>From Step 1, HOIHOIHOI is produced by the reaction:<br>H2O2+HI\u2192H2O+HOIH_2O_2 + HI \\rightarrow H_2O + HOIH2\u200bO2\u200b+HI\u2192H2\u200bO+HOI<br>The rate of this step is proportional to the concentrations of H2O2H_2O_2H2\u200bO2\u200b and HIHIHI:<br>Rate\u00a0of\u00a0formation\u00a0of\u00a0HOI=k1[H2O2][HI]\\text{Rate of formation of } HOI = k_1[H_2O_2][HI]Rate\u00a0of\u00a0formation\u00a0of\u00a0HOI=k1\u200b[H2\u200bO2\u200b][HI] From Step 2, HOIHOIHOI is consumed in the reaction:<br>HOI\u2192H2O+I2HOI \\rightarrow H_2O + I_2HOI\u2192H2\u200bO+I2\u200b<br>The rate of consumption of HOIHOIHOI is proportional to the concentration of HOIHOIHOI:<br>Rate\u00a0of\u00a0consumption\u00a0of\u00a0HOI=k2[HOI]\\text{Rate of consumption of } HOI = k_2[HOI]Rate\u00a0of\u00a0consumption\u00a0of\u00a0HOI=k2\u200b[HOI] Using the steady-state approximation for HOIHOIHOI, we set the rate of formation equal to the rate of consumption:<br>k1[H2O2][HI]=k2[HOI]k_1[H_2O_2][HI] = k_2[HOI]k1\u200b[H2\u200bO2\u200b][HI]=k2\u200b[HOI]<br>Solving for [HOI][HOI][HOI]:<br>[HOI]=k1[H2O2][HI]k2[HOI] = \\frac{k_1[H_2O_2][HI]}{k_2}[HOI]=k2\u200bk1\u200b[H2\u200bO2\u200b][HI]\u200b<\/li>\n\n\n\n<li><strong>Rate of Formation of I2I_2I2\u200b<\/strong>:<br>From Step 2, I2I_2I2\u200b is produced from the reaction of HOIHOIHOI (which we&#8217;ve already solved for):<br>HOI\u2192H2O+I2HOI \\rightarrow H_2O + I_2HOI\u2192H2\u200bO+I2\u200b<br>The rate of formation of I2I_2I2\u200b is proportional to the concentration of HOIHOIHOI:<br>Rate\u00a0of\u00a0formation\u00a0of\u00a0I2=k2[HOI]\\text{Rate of formation of } I_2 = k_2[HOI]Rate\u00a0of\u00a0formation\u00a0of\u00a0I2\u200b=k2\u200b[HOI] Substituting the expression for [HOI][HOI][HOI] into this rate equation:<br>Rate\u00a0of\u00a0formation\u00a0of\u00a0I2=k2\u00d7k1[H2O2][HI]k2=k1[H2O2][HI]\\text{Rate of formation of } I_2 = k_2 \\times \\frac{k_1[H_2O_2][HI]}{k_2} = k_1[H_2O_2][HI]Rate\u00a0of\u00a0formation\u00a0of\u00a0I2\u200b=k2\u200b\u00d7k2\u200bk1\u200b[H2\u200bO2\u200b][HI]\u200b=k1\u200b[H2\u200bO2\u200b][HI]<\/li>\n<\/ol>\n\n\n\n<p>Thus, the rate of formation of I2I_2I2\u200b is given by:<br>Rate&nbsp;of&nbsp;formation&nbsp;of&nbsp;I2=k1[H2O2][HI]\\text{Rate of formation of } I_2 = k_1[H_2O_2][HI]Rate&nbsp;of&nbsp;formation&nbsp;of&nbsp;I2\u200b=k1\u200b[H2\u200bO2\u200b][HI]<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Final Answer:<\/h3>\n\n\n\n<p>The rate of formation of I2I_2I2\u200b is k1[H2O2][HI]k_1[H_2O_2][HI]k1\u200b[H2\u200bO2\u200b][HI], where k1k_1k1\u200b is the rate constant for the first step in the reaction mechanism. This expression indicates that the rate depends on the concentrations of H2O2H_2O_2H2\u200bO2\u200b and HIHIHI.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/07\/learnexams-banner6-150.jpeg\" alt=\"\" class=\"wp-image-250786\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>For the reaction 2H2O2 + 2HI -> 2H2O + I2, the following mechanism is proposed: 1. H2O2 + HI -> H2O + HOI 2. HOI -> H2O + I2 3. H2O2 + I2 -> 2H2O + O2 Derive an expression for the rate of formation of I2 using the steady-state approximation. The Correct Answer and [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-250784","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/250784","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=250784"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/250784\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=250784"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=250784"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=250784"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}