Question

Which of the following statement is incorrect with Williamson synthesis?

• A. It is used to prepare symmetrical and unsymmetrical ethers.
• B. It involves reaction between alkyl halide and sodium alkoxide.
• C. This reaction involves $S_N2$ attack.
• D. Secondary or tertiary alkyl halides gives better results of ether formation.
• E. Alkoxides are not only nucleophiles but also strong bases.

Hint:

Chemistry Tip: For Williamson synthesis, choose primary alkyl halide to favor substitution over elimination.

Answer 1

The Correct Option is D

Concept:
Williamson ether synthesis is a common method for preparing ethers. General reaction: $$RONa + R'X \rightarrow ROR' + NaX$$ where:

• $RONa$ = sodium alkoxide
• $R'X$ = alkyl halide
• $ROR'$ = ether

The mechanism usually follows $S_N2$ pathway.
Step 1: Check statement (A).
By choosing same or different alkyl groups:

• Same groups $\Rightarrow$ symmetrical ether
• Different groups $\Rightarrow$ unsymmetrical ether

So (A) is correct.
Step 2: Check statement (B).
Reaction occurs between alkoxide ion and alkyl halide. So (B) is correct.
Step 3: Check statement (C).
Alkoxide attacks carbon and halide leaves simultaneously: $$S_N2$$ Hence (C) is correct.
Step 4: Check statement (D).
Secondary and tertiary alkyl halides do not give better ether yields because:

• Steric hindrance blocks $S_N2$ attack.
• Strong base (alkoxide) often causes elimination ($E2$).

Best results are obtained with:

• Primary alkyl halides
• Methyl halides

Therefore statement (D) is incorrect.
Step 5: Check statement (E).
Alkoxides are:

• Strong nucleophiles
• Strong bases

So (E) is correct.
Step 6: Final answer.
Incorrect statement is: $$\boxed{\text{Option (D)}}$$ :contentReference[oaicite:0]{index=0}