Question

In diammonium phosphate $(N{H}_4{)}_{2}HP{O}_4$, the percentage of $P_2{O}_5$ is :

• A. 35.87
• B. 46.44
• C. 51.99
• D. 53.78

Answer 1

Answer: (D)

53.78

Molar Mass of Diammonium Phosphate $(N{H}_4{)}_{2}HP{O}_4$ is $28+8+1+31+64=132grams$

Molar Mass of $P_2{O}_5$ is $62+80=142grams$

We know that $2$ moles of diammonium hydrogen sulphate yields $1$ moles of $P_2{O}_5$ i.e $2(N{H}_4{)}_{2}HP{O}_4\to P_2{O}_5$

Mass of $2$ moles of $P_2{O}_5=2\times 132grams=264grams$

Therefore, percentage composition of $P_2{O}_5=\frac{Massof{P}_2{O}_5}{Massof2molesof(N{H}_4{)}_{2}HP{O}_4}$

$=\frac{142}{264}\times 100=53.78$%