Question

Consider the following reactions:

I. Zn + Dil. H₂SO₄ → ZnSO₄ + H2

II. Zn + Conc. H₂SO₄ → ZnSO₄ + SO₂ + H₂O 

III. Zn + HNO₃ → Zn(NO₃)₂ + NH₄ NO₃ + H₂O

Oxidation number of hydrogen changes in

(a) I, II and III

(b) Both I and II

(c) Both II and III

(d) Only I

Answer 1

Correct option is (d) Only I

(No change in oxidation number)

Thus, only in (I) oxidation number of hydrogen changes.