Question

For each of the following reactions:

a) Write the oxidation number for each element above the element. b) Identify the atom being oxidized and reduced. C) Identify the oxidizing reactant and reducing reactant.

a. 3CuO(aq) + 2NH3 (aq) --->   3Cu (s) + N2 (g) + 3H2O (l)

Oxidized:     Reduced:    Oxi. Reactant:   Red. Reactant:

b. Mg (s)   + 2HCl (aq)  ---->   Mg+2(aq) +   2Cl-1 (aq) +   H2 (g)

Oxidized:     Reduced:      Oxi. Reactant:   Red. Reactant:

Answer 1

a)

oxidation state of all elements at the right top corner

3Cu²⁺O^2-(aq) + 2N^3-H⁺¹₃ (aq) --->   3Cu⁰ (s) + N⁰₂ (g) + 3H⁺¹₂O^-2 (l)

here copper is being reduced from +2 to 0 state

nitrogen atom is being oxidized from -3 + 0

CuO is oxidizing agent as it takes up electron and oxidizes others

NH3 is reducing agent

b)

Mg⁰ (s)   + 2H⁺¹Cl^-1 (aq)  ---->   Mg⁺²(aq) +   2Cl^-1 (aq) +   H⁰₂ (g)

Mg is getting oxidized from 0 to +2 and hydrogen is getting reduced from +1 to 0

Mg is reducing agent as it is giving electrons for reduction

HCl is oxidizing agent