What are the oxidation states of phosphorus in the following:

Explanation

(i)`H_(3)^(+1)overset(x-2)(PO)_(3) therefore 3(+1) + x +3 (-2)=0` or `x=+3`
(ii)`overset(x)(P)Coverset(-1)l_(3) therefore x+3 (-1)=0` or `x=+3`
(iii)`Ca_(3)^(+2)P_(2)^(x) therefore 3(+2) + 2 xx x=0=-3`
(iv)`Na_(3)PO_(4) therefore 3(+1) + 2 x +4(-2)=0` or `x=+5`
(v)`overset(x-2)(PO)overset(-1)F_(3) therefore x + 1(-2)+3 (-1)=0` or `x=+5`