A solution of sucrose (molar mass `= 342 g mol^(-1)`) has been prepared by dissolving 68.5 g of sucrose in 1000 g of water. The freezing point of the solution obtained will be `(K_f " for water " = 1.86 K kg mol^(-1))`

Options

A. `- 0.372^@C`
B. `- 0.520^@C`
C. `+ 0.372^@C`
D. `- 0.570^@C`

Answer

A

Explanation

We know, `DeltaT_f= K_fm`
here, `m = (68.5)/342 (1000 g=1 kg)`
`:. DeltaT_f= 0.2000 xx 1.86 = 0.3725^@C`
`T_f=0 -0.3725^@C = -0.3725^@C`