Haloalkanes And Haloarenes

Step 1: Understanding the Concept:
Removal of HBr from a vicinal dibromide gives an alkyne.

Step 2: Detailed Explanation:
C H Br (1,2-dibromoethane) with alcoholic KOH undergoes two successive dehydrohalogenations to form ethyne (C H ).
BrCH CH Br CH =CHBr HC≡CH. This is dehydrobromination.

Step 3: Final Answer:
Dehydrobromination

Step 1: Understanding the Concept:
KCN reacts with alkyl halide via S 2 to give nitrile. Hydrolysis of nitrile gives carboxylic acid.

Step 2: Detailed Explanation:
C H Cl + KCN → C H CN (ethyl cyanide, X) + KCl.
C H CN C H COOH (propanoic acid, Y).
Molecular formula of Y = C H O .

Step 3: Final Answer:
C H O