Question

The ratio of the oxidation state of P in $H_{3}P{O}_3$ and $H_{3}P{O}_4$ is

• A. 3:5
• B. 5:3
• C. 2:5
• D. 5:2

Answer 1

The correct option is A 3:5

We know that the oxidation number of hydrogen and oxygen is +1 and -2 respectively.

Since both $H_{3}P{O}_3$ and $H_{3}P{O}_4$ are stable compounds, the sum of oxidation number of their respective elements adds up to zero.

Considering the oxidation number of P to be 'x',

For $H_{3}P{O}_3$, $3\times (+1)+x+(3\times (-2)=0$

$\Rightarrow x-3=0$

$\Rightarrow x=3$

For $H_{3}P{O}_4$, $3\times (+1)+x+(4\times (-2)=0$

$\Rightarrow x-5=0$

$\Rightarrow x=5$

Thus, the ratio of the oxidation state of P in $H_{3}P{O}_3$ and $H_{3}P{O}_4$ is 3:5.