{"id":199767,"date":"2025-03-12T15:26:40","date_gmt":"2025-03-12T15:26:40","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=199767"},"modified":"2025-03-12T15:26:42","modified_gmt":"2025-03-12T15:26:42","slug":"ch3ch2ch2br-na-cn-%e2%86%92","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/03\/12\/ch3ch2ch2br-na-cn-%e2%86%92\/","title":{"rendered":"CH3CH2CH2Br + Na+ -CN \u2192"},"content":{"rendered":"\n

CH3CH2CH2Br + Na+ -CN \u2192<\/p>\n\n\n\n

The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n

The given reaction:<\/p>\n\n\n\n

[
\\text{CH}_3\\text{CH}_2\\text{CH}_2\\text{Br} + \\text{Na}^+ -\\text{CN} \\rightarrow
]<\/p>\n\n\n\n

Correct Answer:<\/strong>
[
\\text{CH}_3\\text{CH}_2\\text{CH}_2\\text{CN} + \\text{NaBr}
]<\/p>\n\n\n\n

Explanation:<\/h3>\n\n\n\n
    \n
  1. Type of Reaction:<\/strong>
    This is a nucleophilic substitution reaction (S(_N)2 mechanism)<\/strong>. In this reaction, the bromopropane (CH(_3)CH(_2)CH(_2)Br) undergoes substitution with the cyanide ion (CN\u207b) from sodium cyanide (NaCN).<\/li>\n\n\n\n
  2. Mechanism of the Reaction:<\/strong><\/li>\n<\/ol>\n\n\n\n
      \n
    • The propyl bromide (CH\u2083CH\u2082CH\u2082Br)<\/strong> has a polar C-Br bond<\/strong>, where the carbon is partially positive<\/strong> due to the electronegativity of bromine.<\/li>\n\n\n\n
    • The cyanide ion (CN\u207b)<\/strong> is a strong nucleophile and attacks the electrophilic carbon<\/strong> from the backside<\/strong> in a one-step concerted mechanism<\/strong>.<\/li>\n\n\n\n
    • The Br\u207b leaves<\/strong>, and C-CN bond formation<\/strong> occurs simultaneously.<\/li>\n\n\n\n
    • This follows an S(_N)2 mechanism<\/strong> (bimolecular nucleophilic substitution), which occurs in one step with inversion of configuration<\/strong>.<\/li>\n<\/ul>\n\n\n\n
        \n
      1. Product Formation:<\/strong><\/li>\n<\/ol>\n\n\n\n
          \n
        • The propyl bromide (CH\u2083CH\u2082CH\u2082Br)<\/strong> is converted to propyl cyanide (CH\u2083CH\u2082CH\u2082CN)<\/strong>, also known as butanenitrile<\/strong>.<\/li>\n\n\n\n
        • Sodium bromide (NaBr) is formed as a by-product.<\/li>\n<\/ul>\n\n\n\n
            \n
          1. Why S(_N)2 Instead of S(_N)1?<\/strong><\/li>\n<\/ol>\n\n\n\n
              \n
            • Primary alkyl halides<\/strong> (like CH\u2083CH\u2082CH\u2082Br) favor S(_N)2<\/strong> mechanisms because the primary carbon is less sterically hindered<\/strong>, making it easier for the nucleophile to attack.<\/li>\n\n\n\n
            • The S(_N)1 mechanism<\/strong>, which involves a carbocation intermediate, is less favorable here since a primary carbocation is highly unstable<\/strong>.<\/li>\n<\/ul>\n\n\n\n
                \n
              1. Importance of Reaction:<\/strong><\/li>\n<\/ol>\n\n\n\n
                  \n
                • This reaction is useful in organic synthesis for converting alkyl halides to nitriles<\/strong>, which can then be hydrolyzed to carboxylic acids<\/strong> or reduced to primary amines<\/strong>.<\/li>\n<\/ul>\n\n\n\n

                  Thus, the final product is propyl cyanide (butanenitrile), CH\u2083CH\u2082CH\u2082CN<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":"

                  CH3CH2CH2Br + Na+ -CN \u2192 The correct answer and explanation is : The given reaction: [\\text{CH}_3\\text{CH}_2\\text{CH}_2\\text{Br} + \\text{Na}^+ -\\text{CN} \\rightarrow] Correct Answer:[\\text{CH}_3\\text{CH}_2\\text{CH}_2\\text{CN} + \\text{NaBr}] Explanation: Thus, the final product is propyl cyanide (butanenitrile), CH\u2083CH\u2082CH\u2082CN.<\/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-199767","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/199767","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=199767"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/199767\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=199767"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=199767"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=199767"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}