. {CH}₃ {CH}₂ {C} {CH} {A}{{B}{}} {CH}₃ {C} {C}-{CH}₃, A and B are

Correct Answer is : alc. KOH{KOH}KOH and NaNH2{NaNH}₂NaNH2

Correct Answer is : alc. KOH{KOH}KOH and NaNH2{NaNH}₂NaNH2

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CGPET 2014 Solved Paper

Section: Chemistry

Question : 87 of 150

Marks: +1, -0

\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{C} \equiv \mathrm{CH} \overset{A}{\underset{B}{\Rightarrow}} \mathrm{CH}_3 \mathrm{C} \equiv \mathrm{C}-\mathrm{CH}_3, A

B

Solution:

\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{C} \equiv \mathrm{CH} \overset{A}{\underset{B}{\Rightarrow}} \mathrm{CH}_3-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}_3

\underset{\text{but-1-yne}}{\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{C}} \equiv \mathrm{CH} \xrightarrow{\text{Ethanoilic}\; \mathrm{KOH}}

\underset{\text{Intermediate}}{[\mathrm{CH}_3 \mathrm{CH}} = \mathrm{C}= \mathrm{CH}_2] \longrightarrow \underset{\text{but-2-yne}}{\mathrm{CH}_3 \mathrm{C} \equiv \mathrm{CCH}_3}

Acetylene homologues isomerise when heated with ethanolic

\mathrm{KOH}

, the triple bond moving towards the centre of the chain.

When alkynes are heated with sodamide in an inert solvent (paraffin), triple bond shifts towards the end of the chain.

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