Question

An aqueous solution contains 3% and 1.8% by weight urea and glucose respectively. What is the freezing point of solution?
($K_f$= 1.86 Kkg$mo{l}^{-1}$)

• A. $-1.172°C$
• B. $-2.27°C$
• C. $-1.5°C$
• D. None of these

Answer 1

The correct option is A $-1.172°C$

$\Delta T_f=K_f(\frac{n_1+n_2}{W_{\mathrm{solvent}}}\times 1000);\Delta T_f=1.86(\frac{\frac{3}{60}+\frac{1.8}{180}}{95.2}\times 1000)=1.172T_f°-T_f=1.172°C;T_f=-1.172°C$