Question

Density of `2.05 M` solution of acetic acid in water is `1.02g//mL`. The molality of same solution is:
A. `1.14 mol kg^(-1)`
B. `3.28 mol kg^(-1)`
C. `2.28 mol kg^(-1)`
D. `0.44 mol kg^(-1)`

Answer 1

Correct Answer - C
Mass of 1 litre solution of 2.05 M acetic acid = 1020 g
Mass of acetic acid present in it = `2.05xx60=123 g`
Mass of solvent (water) in this solution
`= 1020-123 =897 g`
`therefore` Molality of the solution `=(2.05)/(897)xx1000=2.28 mol kg^(-1)`