Question

The molality of $$90 \% \,H_2SO_4$$ solution is

[density $$= 1.8 \ gm/ml$$]

Answer 1

Correct option is C. 9.18

The density of solution $$= 1.8 \,gm / ml$$

Weight of one litre of solution $$ = 1800 \,gm$$

$$\therefore$$ Weight of $$H_2SO_4$$ in the solution $$ = \dfrac {1800 \times 90}{100} = 1620 \,gm$$

$$\therefore$$ Weight of solvent $$= 1800 - 1620 = 180 \,gm$$

$$\therefore Molality = \dfrac {1620}{98} \times \dfrac {100}{180} = 9.18$$