Question

The oxidation states of phosphorus vary from

(a) -3 to +5

(b) -1 to +1

(c) -3 to +3

(d) -5 to +1

Answer 1

Correct option is (a) -3 to +5

Phosphorous belongs to group 15. It has 5 electrons in its valence shell. So it can either lose 5 e⁻ to attain +5 oxidation state or gain 3 e⁻ to attain −3 oxidation state. Hence its oxidation state varies from −3 in PH₃​ to +5 in H_3​PO₄​.