Question

Please show working clearly for question 4,a&b

Balance the following equation in acidic solution. Identify the reducing agent and the oxidizing agent. Cu + NO_3 rightarrow NO + Cu^2+ (acidic solution)

Answer 1

Balance the following equation in acidic solution.

Cu + NO₃^- --> NO + Cu²⁺

Half reactions:

Cu --> Cu²⁺
NO₃^- --> NO

Identify the oxidation state of each element:

Copper, from 0 to 2+ (this element is oxidized)
Nitrogen, from +5 to 2+ (this element is reduced)
Oxygen is always 2-
*the reducing agent is the one who is oxidized (Cu).
*the oxidizing agent is the one who is reduced (NO₃^-)

Balance the elements and then the electrons for each half reaction:
Cu --> Cu²⁺ + 2e^-
3e^- + NO₃^- --> NO

Balance the charges on each side of the half reactions with H⁺ (acidic solution):
Cu --> Cu²⁺ + 2e^- (already balanced)
4H⁺ + 3e^- + NO₃^- --> NO

Balance the oxygen by adding water:
4H⁺ + 3e^- + NO₃^- --> NO + 2H₂O

Multiply each of the half reactions so that the electron count be the same:
3Cu --> 3Cu²⁺ + 6e^-
8H⁺ + 6e^- + 2NO₃^- --> 2NO + 4H₂O

Sum both half reactions:
3Cu + 8H⁺ + 2NO₃^- --> 3Cu²⁺ + 2NO + 4H₂O
*balanced chemical equation