What are the oxidation states of phosphorus in the following:
(i)`H_(3)PO_(3)` , (ii)`PCl_(3)` , (iii)`Ca_(3)P_(2)`
(iv)`Na_(3)PO_(4)` , (v)`POF_(3)`

Explanation

Let the oxidation state of p be x
(i) `H_(3) PO_(3)`
` 3 + x+ 3(-2) = 0`
` 3 + x - 6 = 0`
`x- 3 =0`
`x= + 3`
(ii) `PCl_(3)`
`x + 3 (-1) =0`
`x- 3 =0`
`x- 3 =0`
(iii) `Ca_(3)P_(2)`
`3(+2) +2 (x) =0`
`6+2x =0`
`2x = -6`
`x = -3`
(iv) `Na_(3)PO_(4)`
`3(+1) + x+ 4(-2) =0`
`3+ x-8=0`
`x-5 = 0`
`x = +5`
(v) `POF_(3)`
`x-5 = 0`
`x = +5`