Question

Which of the following compounds contain phosphorus with an oxidation state of $+5$?

• A. Pyrophosphoric acid
• B. Hypophosphorous acid
• C. Orthophosphorous acid
• D. Hypophosphoric acid

Answer 1

The correct option is A Pyrophosphoric acid

The oxidation state of phosphorus in pyrophosphoric acid $\left(H_4{P}_2{O}_7\right)$ is $+5$. The oxidation state of phosphorus in hypophosphorus acid $\left(H_{3}P{O}_2\right)$ is $+1$, in orthophosphorous acid $\left(H_{3}P{O}_3\right)$ is $+3$ and in hypophosphoric acid $\left(H_4{P}_2{O}_6\right)$ is $+4.$