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

(a) `H_(3)PO_(3) " overset(+1)H_(3) overset(x)P overset(-2)O_(3)`
`3(+1)+x+3(-2)=0 " or " x-3=0 " or " x=+3`
`(b) PCl_(3) : overset(x)P overset(-1) Cl_(3)`
`x+3(-1)=0 " or" x-3=0 " or " x=+3`
(c ) `Ca_(3)P_(2) : overset(+2)Ca_(3) overset(x)P_(2)`
`(+2) +2 (x)=0 " or"2x +6=0 " or" x=-3`
(d) `Na_(3)PO_(4) : overset(+1)Na_(3) overset(x-2)PO_(4)`
`3(+1) +x+4(-2)=0 " or" x-5 =0 " or " x=+5`
(e ) `POF_(3) : overset(x-2-1)POF_(3)`
`x+(-2)+3 (-1)=0 " or " x-5=0 " or " x=+5`