Oxidation states of `P` in `H_4P_2O_5, H_4P_2O_6` and `H_4P_2O_7` are respectively

Options

A. `+ 3, + 4, + 5`
B. `+ 3, + 5, + 4`
C. `+ 5, + 3, + 4`
D. `+ 5, + 4, + 3`

Answer

A

Explanation

`underset(H-O)underset(|)(H-O-P-O-P)underset(O-H)underset(|)(-O-H)" "(H_4P_2O_5)`
Each P atom is connected to 3 oxygen atoms. So oxidation number of `P =+3 .`
`H-O-underset(H-O)underset(|)overset(O)overset(||)P-underset(O-H)underset(|)overset(O)overset(||)P-O-H " "(H_4P_2O_6)`
Each P atom is connected to 2 oxygen atoms by single bonds, one oxygen atom by a double bond and one phosphorus atom by a single bond. So oxidation no. of `P = 2 (+1) +1 (+2) +0 =+4`
`H-O-underset(H-O)underset(|)overset(O)overset(||)P-O-underset(O-H)underset(|)overset(O)overset(||)P-O-H " "(H_4P_2O_7)`
Similarly oxidation number of P `= 3(+1) + 1(+2) =+5 .`