Can someone please help me with these two Chemistry problems?

Question

 In the reaction 2Mg (s) + O₂ (g) + 2H₂O (l) → 2Mg²⁺ (aq) + 4OH^– (aq), which substance is reduced?

A. Mg

B. O

C. H2O

D. OH

E. None of the Above (This is not a redox reaction.)

In the reaction 2H₂O (l) + 2Cl^– (aq) → H₂ (g) + Cl₂ (g) + 2OH^– (aq), which substance is oxidized?

A. H2O

B. Cl

C. H

D. OH

E. None of the Above (This is not a redox reaction.)

Answer 1

In the first question, find which element (or substance) goes to a more negative oxidation number, i.e. which element is reduced. Oxygen in O2 has o.n. = 0. Oxygen in OH- has o.n. = 2-. So, it has gained electrons and is reduced.

Second question I agree with your answer. Cl goes from 1- on the left to zero on the right. It has lost an electron and so was oxidized.