Question

What weight of glycerol should be added to $600\, g$ of water in order to lower its freezing point by $10 \,^?C$ ? $(K_f = 1.86^?\, C\, m^{-1})$

• A. $496 \,g$
• B. $297 \,g$
• C. $310 \,g$
• D. $426\,g$

Answer 1

Answer: (B)

$297 \,g$

Answer 2

$\Delta T_{f} = K_{f} \times m = \frac{K_{f} \times W_{2} \times 1000}{M_{2} \times W_{1}}$ $W_{2} = \frac{10 \times 92 \times 600}{1.86 \times 1000} =296.77\,g$