{"id":337,"date":"2013-10-09T22:50:34","date_gmt":"2013-10-09T22:50:34","guid":{"rendered":"http:\/\/www.studyorgo.com\/blog\/?p=337"},"modified":"2014-02-21T03:22:01","modified_gmt":"2014-02-21T03:22:01","slug":"free-radical-halogenation-module-part-4-practice-quiz","status":"publish","type":"post","link":"https:\/\/www.studyorgo.com\/blog\/free-radical-halogenation-module-part-4-practice-quiz\/","title":{"rendered":"Free Radical Halogenation Module: Part 4: Practice Quiz"},"content":{"rendered":"

This is the fourth and final part of a multi-part module on Free Radical Halogenation.<\/p>\n

View the first part here: Part 1: The Mechanism<\/a><\/p>\n

View the second part here: Part 2: Regioselectivity<\/a><\/p>\n

View the third part here: Part 3: Stereoselectivity<\/a><\/p>\n

 <\/p>\n

Question 1:<\/span><\/p>\n

What principle accounts for the observed regioselectivity of radical bromination that is not observed for radical chlorination of alkenes?<\/p>\n

    \n
  1. Lechatlier\u2019s Principle<\/li>\n
  2. Avagadro\u2019s Lab<\/li>\n
  3. <\/b>Hammond\u2019s Postulate<\/li>\n
  4. Markovnikov Rule<\/li>\n<\/ol>\n

     <\/p>\n

    Question 2:<\/span><\/p>\n

    Which product can NOT be prepared in high yield by radical halogenation of alkanes?<\/p>\n

      \n
    1. <\/b>Iodoethane<\/li>\n
    2. 2-Bromo-2-methylheptane<\/li>\n
    3. Chlorocyclopentane<\/li>\n
    4. 2-Bromo-2,4,4,trimethylpentane<\/li>\n<\/ol>\n

       <\/p>\n

      Question 3:<\/span><\/p>\n

      Predict the major product of the following reaction.<\/p>\n

       <\/p>\n

      \"click<\/a>

      click on image to enlarge<\/p><\/div><\/p>\n

      \"click<\/a>

      A\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0B \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 C \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0D
      click on image to enlarge<\/p><\/div><\/p>\n

       <\/p>\n

       <\/p>\n

      Question 4:<\/span><\/p>\n

      Describe the reaction conditions to produce the following product<\/p>\n

      \"click<\/a>

      click on image to enlarge<\/p><\/div><\/p>\n

        \n
      1. NaBr<\/li>\n
      2. Br2<\/sub><\/li>\n
      3. H2<\/sub>SO4<\/sub>, Br2<\/sub><\/li>\n
      4. <\/b>HBr<\/li>\n<\/ol>\n

         <\/p>\n

         <\/p>\n

         <\/p>\n

         <\/p>\n

        Answers and Explanations:<\/strong><\/span><\/p>\n

        Question 1: \u00a03<\/p>\n

        Difficulty Level: Easy<\/p>\n

        Explanation: Hammond’s Postulate describes the stability of the radical center is outweighed by the extreme exothermicity of radical chlorination (in contrast to bromination, which is endothermic), thus a mixture of chlorinated products is observed.<\/p>\n

         <\/p>\n

        Question 2: 1<\/p>\n

        Difficulty Level: Medium<\/p>\n

        Explanation: Answers 2,3,4 all would start from alkanes containing secondary and tertiary carbon centers, which produce stable radical intermediates for halogenation.\u00a0 Ethane contains two primary carbons coupled to the extreme endothermicity of iodination would yield very little product.<\/p>\n

         <\/p>\n

        Question 3: B<\/p>\n

        Difficulty Level: Medium<\/p>\n

        Explanation: \u00a0The steric strain of the cyclopropane ring will drive the hemolytic cleavage of the 2,4 sigma bond with radical bromine to produce a radical intermediate on carbon 2.\u00a0 Propagation of the radical bromine will result in the formation of product B.\u00a0 Product C and D are not possible while the reagents to produce product A are not listed.<\/p>\n

         <\/p>\n

         <\/p>\n

        Question 4: 4<\/p>\n

        Difficulty Level: Hard<\/p>\n

        Explanation: Addition across the double bond with one equivalent of Br would more easily take place via an electrophilic addition using an equivalent of HBr, while radical bromination would produce dibromo-pentane.<\/p>\n

         <\/p>\n

         <\/p>\n

        There are multiple examples of this reaction to review in the\u00a0StudyOrgo.com Study Mode<\/a>. When ready, test your knowledge in the\u00a0StudyOrgo.com Quiz Mode<\/a>.<\/p>\n

        Not a member yet?\u00a0Sign-Up today!<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

        This is the fourth and final part of a multi-part module on Free Radical Halogenation. View the first part here: Part 1: The Mechanism View the second part here: Part 2: Regioselectivity View the third part here: Part 3: Stereoselectivity   Question 1: What principle accounts for the observed regioselectivity of radical bromination that is […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_mi_skip_tracking":false},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/posts\/337"}],"collection":[{"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/comments?post=337"}],"version-history":[{"count":3,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/posts\/337\/revisions"}],"predecessor-version":[{"id":351,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/posts\/337\/revisions\/351"}],"wp:attachment":[{"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/media?parent=337"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/categories?post=337"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.studyorgo.com\/blog\/wp-json\/wp\/v2\/tags?post=337"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}