pH of a 0.1 M solution of a monobasic acid is 2.0. Its osmotic pressure at a given temperature, K is — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

For a monobasic acid HA, pH = 2.0 means $[H^+] = 10^{-2} \text{ M} = 0.01 \text{ M}$. The concentration of $[H^+] = C\alpha$, where $C = 0.1 \text{ M}$. Thus, $0.1 \times \alpha = 0.01 \Rightarrow \alpha = 0.1$. The van't Hoff factor $i = 1 + \alpha = 1 + 0.1 = 1.1$. The osmotic pressure $\pi = iCRT = 1.1 \times 0.1 \times RT = 0.11RT$. Therefore, correct answer is B.