Question

Density of a 2.05M solution of acetic acid in water is 1.02 g/mL. The molality of the solution is

Answer 1

answer is as follows

Answer 2

Answer : The molality of the solution is, 2.32 mole/Kg

Solution : Given,

Molarity of solution = 2.05 M

Density of water = 1.02 g/ml

The relation between the molarity, molality and the density of the solution is,

$d=M[\frac{1}{m}+\frac{M_b}{1000}]$

where,

d = density of solution  = 1.02 g/mole

m = molality of solution  = ?

M = molarity of solution  = 2.05 mole/L

$M_b$ = molar mass of solute(acetic acid) = 60 g/mole

Now put all the given value in this formula, we get the molality of the solution.

$1.02g/ml=2.05mole/L[\frac{1}{m}+\frac{60g/mole}{1000}]$

$m=2.32mole/Kg$

Therefore, the molality of the solution is, 2.32 mole/Kg