The density of 2.0 M solution of a solute is `1.2 g mL^(-1)`. If the molecular mass of the solute is `100 g mol^(-1)`, then the molality of the solution is

Options

A. 2.0m
B. 1.2m
C. 1.0m
D. 0.6m

Answer

A

Explanation

2 M solution means that 2 moles of solute are present in 1000 mL of solution .
Wt. fo solution ` = 1000 xx 1.2 = 1200 g`
Wt. of solute `= 2 xx 100 = 200 g`
Wt. of Solvent ` = 1200 -200 = 100g`
Molality ` = (2 xx 1000)/(100) = 2 m`