Chemistry Forum

Chlorine gas is bubbled through a solution of nickel sulfate. Using standard reduction potentials, would a reaction occur?

The half reactions must begin with the reactants available: Cl[sub]₂[/sub], Ni 2+ and SO[sub]₄[/sub] 2- ions.

The 2 half reactions are:
Cl[sub]₂[/sub] + 2e => 2Cl- Eo = +1.36 V
Ni 2+ + 2e => Ni Eo = -0.24 V

The more positive reduction potential will reduce, moving in the forward direction. Cl’s half reaction is viable because if it moves forward chlorine gas is available initially as per the scenario.

Though, the more negative reduction potential will move in the backward reaction, meaning for Ni, it starts with Ni and forms Ni 2+ ions. Since I had Ni 2+ as the only possible reactant available from the NiSO[sub]₄[/sub] solution, I then concluded the reaction would not occur. The answer says that the reaction will occur and I’m unsure of which part of my reasoning is flawed.

Its not clear do you have Ni metal available or not. If yes Ni is immersed into the NiSO₄ solution. Chlorine is an oxidiser and will react with the Ni to form NiCl₂. If only Ni 2+ is available then it could react from Ni 2+ to Ni 3+.

The question doesn’t state specifically whether Ni is available in the solution. The answer is ‘yes a reaction occurs’, with the half reactions being given as:
Cl₂ + 2e => 2Cl
Ni 2+ + 2e => Ni

Complete reaction being:
Cl₂ + Ni => 2Cl- + Ni₂+

Disaggree

The solution is NiSO₄. In this Chlorine Cl₂ will be inserted.
We have Ni 2+, SO₄ 2- and Cl₂.
There is no reaction Ni => Ni 2+ + 2e-

Cl₂ + 2e => 2Cl
Ni 2+ + 2e => Ni

This would be both reduction, no oxidation

You cannot add both, because you need an Oxidation Ni => Ni 2+ + 2e-

Cl₂ + Ni => 2Cl- + Ni₂+

This would happen if metallic Nickel would be present.
But you have only Nickel ions, no metal.