Question

In which of the following oxidation state of phosphorous is +3?

• A. Orthophosphoric acid
• B. Pyrophosphoric acid
• C. Orthophosphorous acid
• D. Metaphosphoric acid

Answer 1

Answer: (C)

Orthophosphoric acid $H_3{P}^{+5}{O}_4$
Pyrophosphoric acid $H_4{P}_2^{+5}{O}_7$
Orthophosphorous acid $H_3{P}^{+3}{O}_3$
Metaphosphoric acid $H{P}^{+5}{O}_3$
Thus, orthophosphoric acid has +3 oxidation state