Question

What is the expected freezing-point depression for a solution that contains 2.0 mol of KCI

(electrolyte) dissolved in 1.0 kg of water? (K,- -1.86°C/m.)
a.-7.44 °C
C. +7.44 °C
b.-4.77 °C
d. +4.7 °C

Answer 1

a. -7.44 °C

Step-by-step explanation:

Hello there!

In this case, since the freezing point depression formula is:

`\Delta T_f=-i*m*Kf`

Thus, since the Van't Hoff's factor is 2 for KCl as it ionizes in K⁺ and Cl⁻, the molarity is 2.0 m (2.0mol/1.0kg) and the freezing point depression constant is 1.86 °C/m, we calculate the freezing point depression as follows:

`\Delta T_f=-2*2.0m*1.86\°C /m\\\\\Delta T_f=-7.44\°C`

Therefore, the answer is a. -7.44 °C.

Regards!