Question

$105\, ml$ of pure water at $4^{\circ} C$ is saturated with $NH _{3}( g )$ producing a solution of density $0.9\, g /\, ml$. If this solution contains $30 \%$ of $NH _{3}$ by mass, therefore the total volume of solution is:

• A. 250 ml
• B. 125 ml
• C. 166.67 ml
• D. 111.11 ml

Answer 1

Answer: (C)

Let final vol. of solution be $V \,ml$

$\therefore $ Weight of solution $=V \times 0.9 \,g$ and $wt .$ of $NH _{3}$

$=(V \times 0.9-105) \,g$

$\therefore V \times 0.9-105=V \times 0.9 \times 0.3$

$\therefore V \times 0.9 \times 0.7=105$

Or $V=\frac{105}{0.9 \times 0.7}=\frac{105}{0.63} \,ml =166.67\, ml$