Question

The mass percentage of $O$ and $H$ present in monosodium phosphate are respectively:

• A. $53.33\%,1.66\%$
• B. $23.18\%,25.83\%$
• C. $19.17\%,53.33\%$
• D. $23.18\%,53.33\%$

Answer 1

The correct option is A $53.33\%,1.66\%$

Molecular formulaof monosodium phosphate = $Na{H}_{2}P{O}_4$
$\text{Molecular mass}=23+(2\times 1)+31+(4\times 16)=120\text{amu}$
$\text{Therefore mass percentage of O}=\left(64/120\right)\times 100=53.33\%$
$\text{Mass percentage of H}=\left(2/120\right)\times 100=1.66\%$