Question

Identify the products X and Y formed in the following reactions:

(i) CH3CH2OH + PCl5 → X + POCl3 + HCl

(ii) CH3Br + AgF → Y + AgBr

Hint:

To remember the Swarts reaction, think of it as the "F-exchange." It is specifically used because direct fluorination of alkanes is often too violent to control!

Answer 1

Concept:
The reactions involve substitution of functional groups in organic compounds.

Reaction (i): Conversion of alcohols to alkyl halides using phosphorus pentachloride (PCl5). The –OH group is replaced by a chlorine atom.
Reaction (ii): The Swarts Reaction, which is used for the preparation of alkyl fluorides. It involves the exchange of a halogen (usually Br or Cl) with a metal fluoride such as AgF, Hg2F2, or CoF2.

Step 1: Identifying Product X.
CH3CH2OH + PCl5 → CH3CH2Cl + POCl3 + HCl

Thus, X is chloroethane (ethyl chloride).

Step 2: Identifying Product Y.
CH3Br + AgF → CH3F + AgBr

Thus, Y is fluoromethane (methyl fluoride).