Question

The correct descending order of the heat liberated (in kJ) during the neutralization of the acids CH$_3$COOH (W), HF (X), HCOOH (Y) and HCN (Z) under identical conditions is \[ K_a(\text{CH}_3\text{COOH}) = 1.8 \times 10^{-5}, \quad K_a(\text{HCOOH}) = 1.8 \times 10^{-4}, \quad K_a(\text{HCN}) = 4.9 \times 10^{-10}, \quad K_a(\text{HF}) = 3.2 \times 10^{-4} \]

• A. Y > X > Z > W
• B. X > Y > W > Z
• C. W > X > Y > Z
• D. Z > W > Y > X
• E. Z > Y > X > W

Hint:

Higher $K_a$ ⇒ stronger acid ⇒ more heat of neutralization.

Answer 1

The Correct Option is B