Question

The percentage of $P_2{O}_5$ in diammonium hydrogen phosphate $\left[{\left(N{H}_4\right)}_{2}HP{O}_4\right]$ is :

• A. $23.48\%$
• B. $53.78\%$
• C. $46.96\%$
• D. $71.0\%$

Answer 1

The correct option is B $53.78\%$

The molar mass of diammonium hydrogen phosphate is 132 g/mol and that of $P_2{O}_5$ is 142 g/mol.
1 mole of diammonium hydrogen phosphate contains 0.5 mol of $P_2{O}_5$.
132 g of diammonium hydrogen phosphate will contain 71 g of $P_2{O}_5$.
100 g of diammonium hydrogen phosphate will contain $\frac{71}{132}\times 100=53.78$ %
Hence, the percentage of $P_2{O}_5$ in diammonium hydrogen phosphate $\left[{\left(N{H}_4\right)}_{2}HP{O}_4\right]$ is $53.78$%