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CBSE Class 12 Chemistry 2020 Outside Delhi Set 1 Solved Paper

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Question : 32 of 37
Marks: +1, -0
(i) Write the structure of major alkene formed by β\beta-elimination of 2, 2, 3-trimethyl-3bromopentane with sodium ethoxide in ethanol.
(ii) Which one of the compounds in the following pairs is chiral?
(iii) Identify (A) and (B) in the following:
OR
How can you convert the following?
(i) But-1-ene to 1-iodobutane
(ii) Benzene to acetophenone
(iii) Ethanol to propanenitrile
Solution:  
(i) CH3−C∣CH3∣CHC∣3−C∣CH3∣Br−CH2−CH3\mathrm{CH}_3- \overset{\mathrm{CH}\overset{\vert}{\mathrm{C}}_3}{\overset{\vert}{\underset{\mathrm{CH}_3}{\underset{\vert}{\mathrm{C}}}}} - \overset{\mathrm{Br}}{\overset{\vert}{\underset{\mathrm{CH}_3}{\underset{\vert}{\mathrm{C}}}}} - \mathrm{CH}_2- \mathrm{CH}_3 →−HBrC2H5ONa/C2H5OHCH3−C∣CH3∣CH3−C∣CH3=CH−CH33,4,4-Trimethylpent-2-ene (major)\xrightarrow[\mathrm{-HBr}]{ \mathrm{C}_2\mathrm{H}_5\mathrm{ONa} / \mathrm{C}_2\mathrm{H}_5\mathrm{OH} } \underset{\text{3,4,4-Trimethylpent-2-ene (major)}}{ \mathrm{CH}_3- \overset{\mathrm{CH}_3}{\overset{\vert}{\underset{\mathrm{CH}_3}{\underset{\vert}{\mathrm{C}}}}} - \underset{\mathrm{CH}_3}{\underset{\vert}{\mathrm{C}}} = \mathrm{CH}- \mathrm{CH}_3 } +CH3−C∣CH3∣CHC∣3−C∥CH2−CH2−CH32-ethyl-3, 3-dimethylbut-1-ene+ \underset{\text{2-ethyl-3, 3-dimethylbut-1-ene}}{ \mathrm{CH}_3- \overset{\mathrm{CH}\overset{\vert}{\mathrm{C}}_3}{\overset{\vert}{\underset{\mathrm{CH}_3}{\underset{\vert}{\mathrm{C}}}}} - \overset{\mathrm{CH}_2}{\overset{\parallel}{\mathrm{C}}} - \mathrm{CH}_2- \mathrm{CH}_3 }
OR
(iii) C2H5OH→RedP/Br2CH3−CH2−Br→Aq. ethanolKCN\mathrm{C}_2\mathrm{H}_5\mathrm{OH} \xrightarrow{ \mathrm{RedP} / \mathrm{Br}_2 } \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{Br} \xrightarrow[ \text{Aq. ethanol} ]{ \mathrm{KCN} } CH3CH2CNPropanenitrile\underset{\text{Propanenitrile}}{\mathrm{CH}_3\mathrm{CH}_2\mathrm{CN}}
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