Question

When butan-2-ol is dehydrated using sulphuric acid, the concentration of acid and temperature needed respectively is

• A. \(60%\) conc. and \(373~\text{K}\)
• B. \(20%\) conc. and \(373~\text{K}\)
• C. \(20%\) conc. and \(363~\text{K}\)
• D. \(95%\) conc. and \(373~\text{K}\)

Hint:

Primary, secondary, and tertiary alcohols require different conditions for dehydration reactions.

Answer 1

The Correct Option is A

Step 1: Reaction type.
Dehydration of secondary alcohols requires moderately concentrated sulphuric acid and controlled heating.
Step 2: Reaction conditions.
Butan-2-ol undergoes elimination in the presence of about \(60%\) sulphuric acid at \(373~\text{K}\).
Step 3: Conclusion.
Thus, the correct condition is \(60%\) sulphuric acid and \(373~\text{K}\).