Question

Phosphoric acid is widely used in carbonated beverages, detergents, toothpaste and fertilizers. The mass percentages of $H,P$ and $O$ in phosphoric acid are $H-3.06P-31.63\%,O-65.31\%$. The atomic masses $H=1,P=31$ and $O=16$.

• A. True
• B. False

Answer 1

The correct option is A True

Molecular formula of phosphoric acid is $H_3{PO}_4$.

$\therefore$ Molecular mass of $H_3{PO}_4=1\times 3+31\times 1+16\times 4=98$

$\therefore$ Mass percentage of $H=\frac{1\times 3}{98}\times 100$%$=3.06$%

$\therefore$ Mass percentage of $P=\frac{31\times 1}{98}\times 100$%$=31.63$%

$\therefore$ Mass percentage of $O=\frac{16\times 4}{98}\times 100$%$=65.31$%

Answer is true.