JEE Advance - Chemistry (2011 - Paper 1 Offline - No. 16)

An acyclic hydrocarbon P, having molecular formula C₆H₁₀, gave acetone as the only organic product through the following sequence of reactions, in which Q is an intermediate organic compound.

The structure of compound P is

CH₃CH₂CH₂CH₂ $$-$$ C $$\equiv$$ C $$-$$ H

H₃CH₂C $$-$$ C $$\equiv$$ C $$-$$ CH₂CH₃

IIT-JEE 2011 Paper 1 Offline Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 25 English Option 3

IIT-JEE 2011 Paper 1 Offline Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 25 English Option 4

Explanation

(i) When 3,3-dimethyl but-1-yne reacts with dil. $\mathrm{H}_2 \mathrm{SO}_4$ in presence of $\mathrm{HgSO}_4$, ketone is formed.

IIT-JEE 2011 Paper 1 Offline Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 25 English Explanation 1

(ii) The ketone is reduced to secondary alcohol in presence of sodium borohydride $\left(\mathrm{NaBH}_4\right)$ ethanol).

IIT-JEE 2011 Paper 1 Offline Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 25 English Explanation 2

(iii) Reaction of acid with alcohol results in dehydration forming an alkene. During the process, methyl shift results in rearrangement of carbocation which further leads to the formation of alkene.

IIT-JEE 2011 Paper 1 Offline Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 25 English Explanation 3

The product 2,3-dimethyl but-2-ene undergoes ozonolysis to form two moles acetone.

IIT-JEE 2011 Paper 1 Offline Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 25 English Explanation 4

Two moles of acetone is the final product of the reaction.

Compound P is 3,3-dimethyl butyne.

JEE Advance - Chemistry (2011 - Paper 1 Offline - No. 16)

Explanation

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