{"id":221217,"date":"2025-05-29T09:20:21","date_gmt":"2025-05-29T09:20:21","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=221217"},"modified":"2025-05-29T09:20:23","modified_gmt":"2025-05-29T09:20:23","slug":"the-formula-c2h2br2-and","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/29\/the-formula-c2h2br2-and\/","title":{"rendered":"The formula C2H2Br2 and"},"content":{"rendered":"\n

) The formula C2H2Br2 and<\/p>\n\n\n\n

(b) The formula C2Br2Cl2. In each instance designate compounds that are cis-trans isomers of each other. Predict the dipole moment of each one.<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

To address this question, we will examine two chemical formulas:<\/p>\n\n\n\n

(a) C\u2082H\u2082Br\u2082<\/strong>
(b) C\u2082Br\u2082Cl\u2082<\/strong><\/p>\n\n\n\n

For each, we will identify the possible cis-trans<\/em> isomers (geometric isomers) and predict their dipole moments<\/strong>.<\/p>\n\n\n\n

\n\n\n\n

(a) C\u2082H\u2082Br\u2082<\/strong><\/h3>\n\n\n\n

This compound is a dibromoethene<\/strong> with two hydrogen atoms and two bromine atoms on a carbon-carbon double bond. The basic structure is:<\/p>\n\n\n\n

H\u2013C=C\u2013H<\/strong>, with two Br atoms substituting for two of the H atoms.<\/p>\n\n\n\n

There are two geometric isomers<\/strong>:<\/p>\n\n\n\n

    \n
  1. Cis-1,2-dibromoethene<\/strong>\n
      \n
    • Structure: Br and Br on the same side<\/em> of the double bond.<\/li>\n\n\n\n
    • The two dipole moments from Br atoms add up partially<\/strong>, resulting in a net dipole moment<\/strong> (non-zero).<\/li>\n<\/ul>\n<\/li>\n\n\n\n
    • Trans-1,2-dibromoethene<\/strong>\n
        \n
      • Structure: Br atoms on opposite sides<\/em>.<\/li>\n\n\n\n
      • The dipoles from the two Br atoms cancel each other out<\/strong>, leading to a zero or very small dipole moment<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n

        Thus, these are cis-trans isomers<\/strong> due to the restricted rotation of the C=C double bond and different spatial arrangements of the substituents.<\/p>\n\n\n\n

        \n\n\n\n

        (b) C\u2082Br\u2082Cl\u2082<\/strong><\/h3>\n\n\n\n

        This is a tetra-substituted ethene<\/strong> where all substituents are halogens. Isomerism depends on how Br and Cl atoms are arranged around the double bond.<\/p>\n\n\n\n

        Two cis-trans isomers<\/strong> possible:<\/p>\n\n\n\n

          \n
        1. Cis-isomer (cis-1,2-dibromo-1,2-dichloroethene)<\/strong>\n
            \n
          • Br and Cl are on the same side<\/em> respectively.<\/li>\n\n\n\n
          • This arrangement leads to net dipole moments<\/strong>, making it polar<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
          • Trans-isomer (trans-1,2-dibromo-1,2-dichloroethene)<\/strong>\n
              \n
            • Each carbon has one Br and one Cl, arranged across from each other.<\/li>\n\n\n\n
            • Due to vector cancellation of bond dipoles, the dipole moment is lower<\/strong>, possibly close to zero<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n
              \n\n\n\n

              Summary of Dipole Moments<\/strong><\/h3>\n\n\n\n
              Compound<\/th>Isomer<\/th>Dipole Moment Prediction<\/th><\/tr><\/thead>
              C\u2082H\u2082Br\u2082<\/td>Cis<\/td>Non-zero (polar)<\/td><\/tr>
              <\/td>Trans<\/td>\u2248 0 (non-polar)<\/td><\/tr>
              C\u2082Br\u2082Cl\u2082<\/td>Cis<\/td>Non-zero (polar)<\/td><\/tr>
              <\/td>Trans<\/td>Low or \u2248 0<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
              \n\n\n\n
              \n

              Conclusion (300 words)<\/strong><\/h3>\n\n\n\n

              The compounds C\u2082H\u2082Br\u2082 and C\u2082Br\u2082Cl\u2082 are examples of molecules that can exhibit geometric (cis-trans) isomerism<\/strong> due to the presence of a carbon-carbon double bond, which prevents free rotation. In C\u2082H\u2082Br\u2082<\/strong>, the two bromine atoms can be either on the same side (cis<\/strong>) or opposite sides (trans<\/strong>) of the double bond. In the cis-isomer<\/strong>, the molecular dipoles of the Br atoms reinforce each other, leading to a net dipole moment<\/strong> and hence a polar molecule<\/strong>. In contrast, the trans-isomer<\/strong> has its dipoles canceling out, resulting in a non-polar molecule<\/strong> with a near-zero dipole moment.<\/p>\n<\/div><\/div>\n\n\n\n

              Similarly, C\u2082Br\u2082Cl\u2082<\/strong> has four halogen atoms around the double bond: two bromines and two chlorines. Depending on their spatial arrangement, the molecule can exist in cis<\/strong> and trans<\/strong> forms. In the cis-isomer<\/strong>, each pair of like atoms (Br-Br and Cl-Cl) are on the same side, producing a net dipole moment due to their unequal electronegativities and vector directions\u2014making the molecule polar<\/strong>. In the trans-isomer<\/strong>, opposing positions of Br and Cl on each carbon lead to cancellation of dipoles<\/strong>, resulting in a lower overall dipole moment<\/strong> or potentially a non-polar structure.<\/p>\n\n\n\n

              In both cases, cis-isomers are generally polar<\/strong>, and trans-isomers are less polar or non-polar<\/strong>, a principle that helps in predicting physical properties like boiling points and solubility based on molecular geometry and polarity.<\/p>\n\n\n\n

              \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

              ) The formula C2H2Br2 and (b) The formula C2Br2Cl2. In each instance designate compounds that are cis-trans isomers of each other. Predict the dipole moment of each one. The Correct Answer and Explanation is: To address this question, we will examine two chemical formulas: (a) C\u2082H\u2082Br\u2082(b) C\u2082Br\u2082Cl\u2082 For each, we will identify the possible cis-trans […]<\/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-221217","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/221217","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=221217"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/221217\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=221217"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=221217"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=221217"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}