Question

The density of $93\%$ $H_{2}S{O}_4$ by volume is $1.984gm{l}^{-1}$. The molality of a $1$ L solution is:

• A. $10.0$
• B. $8.6$
• C. $9.0$
• D. $9.1$

Answer 1

The correct option is C $9.0$

$100$ ml of solution contains $93$ g of $H_{2}S{O}_4$.
The density of solution is $1.984gm{l}^{-1}$.

The weight of the solution is $100\times 1.984=198.4$ g.
The weight of water is $=198.4-93=105.4$ g.
The molality of the solution is (m) $=\frac{\text{Number of moles}}{\text{Weight of water in kg}}=\frac{93}{98\times \frac{105.4}{1000}}=9.003\simeq 9.0$