Question

Phosphorus has the oxidation state of $+3$ in:

• A. Ortho phosphoric acid
• B. Phosphorus acid
• C. Meta phosphoric acid
• D. Pyrophosphoric acid

Answer 1

The correct option is B Phosphorus acid

Oxidation state of hydrogen $=+1$

Oxidation state of oxygen $=-2$

In Ortho phosphoric acid($H_{3}P{O}_4$), phosphorus has the oxidation state of $+5$.

In phosphorus acid($H_{3}P{O}_3$), phosphorus has the oxidation state of $+3$.

In meta phosphoric acid($H^{}P{O}_3$), phosphorus has the oxidation state of $+5$.

In pyrophosphoric acid ($H_4{P}_2{O}_7$), phosphorus has the oxidation state of $+5$.

So only B) is correct option.