Question

The freezing point of 1 molal NaCl solution assuming NaCl to be 100% dissociated in water is: ($K_f=1.86KMolarit{y}^{-1}$)

• A. $-1.86{}^{\circ }C$
• B. $-3.72{}^{\circ }C$
• C. $+1.86{}^{\circ }C$
• D. $+3.72{}^{\circ }C$

Answer 1

Answer: (B)

$-3.72{}^{\circ }C$

The depression in freezing point of 1 molal $NaCl$ solution assuming $NaCl$ to be 100% dissociated in water is

$=i\times K_f\times molality$

$=2\times 1.86\times 1$

$=3.72$

Freezing point - 0-3.72= $-{3.72}^0$ C