Question

P and Q combine to form two compounds \( PQ_2 \) and \( PQ_3 \). If 1 g \( PQ_2 \) in 51 g benzene gives depression of freezing point \(0.8^\circ C\) and 1 g \( PQ_3 \) gives \(0.625^\circ C\). ( \(K_f = 5.1\) ). Find atomic masses of P and Q.

• A. 35, 55
• B. 45, 45
• C. 55, 45
• D. 55, 35

Hint:

Colligative trick: \begin{itemize} \item Same solvent mass ⇒ depression ∝ \(1/M\). \end{itemize}

Answer 1

The Correct Option is D