Question

The heats of neutralisation of CH\(_3\)COOH, HCOOH, HCN and H\(_2\)S are \(-13.2, -13.4, -2.9\) and \(-3.8\) kcal per equivalent respectively. Arrange the acids in increasing order of acidic strength.

• A. HCOOH > CH\(_3\)COOH > H\(_2\)S > HCN
• B. CH\(_3\)COOH > HCOOH > H\(_2\)S > HCN
• C. H\(_2\)S > HCOOH > CH\(_3\)COOH > HCN
• D. HCOOH > H\(_2\)S > CH\(_3\)COOH > HCN

Hint:

Strong acids release more heat during neutralization.

Answer 1

The Correct Option is B

Step 1: Greater heat of neutralization implies stronger acid.

Step 2: Order based on values:
\[ \text{HCN} < \text{H}_2\text{S} < \text{CH}_3\text{COOH} < \text{HCOOH} \]