Question

Molarity of 26% (w/w) ammonia solution, having a density of $0.85g/ml$ is:

• A. $12.5M$
• B. $12.0M$
• C. $13.5M$
• D. $13M$

Answer 1

Answer: (D)

$13M$

Given, concentration of ammonia solution is $26$% $w/w$.

So, we have $26$ g of $N{H}_3$ in $100$ g of solution.

$\therefore$ Moles of $N{H}_3=\frac{26}{17}=1.53$ moles

Density $=0.85g/ml$

Volume of solution $=\frac{100}{0.85}$

$=117.64ml$
$\therefore \text{Molarity}=\frac{1.53\times 1000}{117.64}=13M$