Question

How many electrons are required to balance the following half-reaction?

Au + 4 Cl- ⟶ AuCl4-

A. 2 electrons on the products side

B. 2 electrons on the reactants side

C. 3 electrons on the products side

D. 3 electrons on the reactants side
Please help ASAP!!! :(

Answer 1

Option C

Step-by-step explanation:

Au + 4Cl- ⟶ AuCl4-

Notice carefully that in reactant side, you have 4 negative charges and in products side you have 1 negative charge, so you need 3 electrons on the products side to ballance.

Au + 4Cl- ⟶ AuCl4- + 3e⁻

The anion AuCl₄⁻ comes from the Chloroauric acid with this dissociation.

HAuCl₄ → H⁺ + AuCl₄⁻