Question

Calculate the boiling point and freezing point of the following solutions:

1. 0. 575 molal aqueous solution

2. 1o g of C₆ H₁₂ O₆ dissolved in 259 g water

3. 0.5 mole Br₂ dissolved in 507 g chloroform

Answer 1

1. We know that molality of solution= 0.575

So,

$\Delta T_b=K_bm$

$\Delta T_b= 0.52×0.575$

$\Delta T_b= 0.299 K$ $Mole=\frac{10}{180}$

For freezing point

$\Delta T_f=K_fm$

$\Delta T_f=1.86×0.575$

$\Delta T_f=1.695 K$

2. 10 g of glucose

Mole of gas

$Mole=\frac{10}{180}$

$\Delta T_b= 0.52×0.214$

$\Delta T_b= 0.11 K$

$\Delta T_f= 01.86×0.214$

$\Delta T_b= 0.398 K$

3. Mole of bromine= 0.5

Mass of chloroform= 507g

$\Delta T_b= 0.52×0.986$

$\Delta T_b= 0.512 K$

$\Delta T_f= 01.86×.986=1.83 K$