IIT-JEE 2012 · Paper 2 · Chemistry Q28

← IIT-JEE 2012 · Paper 2

ChemistrySingle correct+3 / -1Question 28 of 60

The major product H of the given reaction sequence is
$\ce{CH3-CH2-CO-CH3 ->[CN^-] G ->[95\%\ H2SO4][Heat] H}$

\ce{CH3-CH=C(CH3)-COOH}

\ce{CH3-CH=C(CH3)-CN}

\ce{CH3-CH2-C(OH)(CH3)-COOH}

\ce{CH3-CH=C(CH3)-CO-NH2}

Answer and worked solution

Official answer: A

Step 1. Cyanide adds to the ketone: G is the cyanohydrin $\ce{CH3CH2C(OH)(CH3)CN}$ .

Step 2. Hot 95% $\ce{H2SO4}$ dehydrates the tertiary alcohol (towards the more substituted alkene, conjugated with the nitrile) and hydrolyses $\ce{-CN}$ to $\ce{-COOH}$ :
$\mathbf H=\ce{CH3CH=C(CH3)COOH}\ (\text{2-methylbut-2-enoic acid}).$

(A)

Topics:Nucleophilic addition Carboxylic acids

← Previous question Next question →

IIT-JEE 2012 · Paper 2, Chemistry question 28