Hard soft acid base theory, i'm not understanding it

[lil_angel_007]

Homework Statement

the question asks to determine if the equilibrium is greater, equal or less than 1. one of the equation is the following:
[CuI4]2- (aq) + [CuCl4]3- (aq) ↔ [CuCl4]2-(aq) + [CuI4]3- (aq)

Homework Equations

The Attempt at a Solution

the solution given was:
the answer using the HSAB theory is:
HA-SB + SA-HB <-> HA-HB + SA-SB
(respectively) so equilibrium lies towards the products. I don't know how they labeled some of these elements:
i understand that in the first product Copper with an oxidation state of 2+ is a hard acid, Iodine is a soft base with oxidation state of 1-. In the second product, copper is a soft acid with an oxidation state of 1+ (am i right) and Cl is a soft base. Then in the products: i see copper is a hard acid with an oxidation state of 2+ but why is Cl a hard base? in the second product copper is a soft acid (ox state of 1+) and I is a soft base..

basically my question is why is the chloride ion a hard base in the second product?

 

[Nino MMP]

The answer using the HSAB theory is: HA-SB + SA-HB <-> HA-HB + SA-SB (respectively) so equilibrium lies towards the products. Copper with an oxidation state of 2+ is a hard acid, Iodine is a soft base with oxidation state of 1-. Copper is a soft acid with an oxidation state of 1+ and Chloride is a hard base. The chloride ion is a hard base in the second product because it is more electronegative than Iodine, making it more likely to accept electrons from the copper ion. This makes the reaction favour the products, as the hard acid and hard base are forming the product, and the soft acid and soft base are forming the reactant.