Question

1.00 g of a non-electrolyte solute (molar mass 250 g mol⁻¹) was dissolved in 51.2 g of benzene. If the freezing point depression is constant, K_f of benzene is 5.12 K kg mol⁻¹, and the freezing point of benzene will be lowered by ______.

Options

• 0.3 K

• 0.5 K

• 0.4 K

• 0.2 K

Answer 1

1.00 g of a non-electrolyte solute (molar mass 250 g mol⁻¹) was dissolved in 51.2 g of benzene. If the freezing point depression is constant, K_f of benzene is 5.12 K kg mol⁻¹, and the freezing point of benzene will be lowered by 0.4 K.

Explanation:

ΔT = K_fm = `("K"_"f" xx "W"_2 xx 1000)/("M"_2"W"_1)`

= `5.12 xx 1/250 xx 1000/51.2`

= 0.4 K