Which half-reaction shows conservation of charge?
(1) Cu + e- --> Cu+ (3) Cu+ --> Cu + e-
(2) Cu2+ + 2e- --> Cu (4) Cu2+ -->Cu + 2e-



Answer :

PhyCS
(2) Cu2+ + 2e --> Cu shows conservation of charge because all the charges hold constant between the end of the reaction and beginning of the reaction.

Answer:

(2) Cu2+ + 2e- --> Cu

Explanation:

As per the principle of conservation of charge, for a given equation, the net charge on the reactant side (left side) must be equal to that on the product (right side).

Based on the given options:

1) Cu + e-  → Cu+

Left side = -1 ;  Right side = +1

Charge is not conserved

2) Cu+ → Cu + e-

Left side = +1, Right side = -1

Charge is not conserved

3) Cu2+ + 2e- → Cu

Left side = (+2) + (-2) = 0;  Right side = 0

Charge is conserved

4) Cu2+ → Cu + 2e-

Left side = +2;  Right side = -2

Charge is not conserved