Question

The freezing point of 0.1 m aqueous solution of urea, if K_f for water is 1.86 K kg mol^-1 is ______.

Options

• 1.86 °C

• −1.86 °C

• 0.186 °C

• −0.186 °C

Answer 1

The freezing point of 0.1 m aqueous solution of urea, if K_f for water is 1.86 K kg mol^-1 is −1.86 °C.

Explanation:

ΔT_b = k_b × m

= 1.86 × 0.1

= 0.186

`ΔT_b = T_f^0 - T_f`

0.186 = 0 − T_f

T_f = 0.186