Question

Which is/are weaker acid than water?

• A. Alcohols
• B. Termirlal alkynes
• C. Mercaptans
• D. Both (a) and (b)

Answer 1

Answer: (D)

Both (a) and (b)

Answer 2

Since the S-H bond in mercaptant is weaker than $O-H$ bond in alcohols. Therefore, mercaptans are stronger acid than alcohols. Further since both alkoxide ions $(RO^-)$ and acetylide ion $(RC\equiv C^-)$ react with $H_2O$ to give the corresponding alcohol and acetylene respectively. Hence, both alcohols and terminal alkynes are weaker acid than water.