# Influence of adding an acid to an equilibrium reaction that is not part of an equilibrium reaction [closed]

Question:

The equation of chemical equilibrium reaction is the following: $$\ce{[Cu(OH2)4]^2+ + 4Cl- <=> [CuCl4]^2- + 4H2O}$$ The $\ce{[Cu(OH2)4]^2+}$ ions are of blue colour, while the $\ce{[CuCl4]^2-}$ ions are of yellow colour. The mixture at equilibrium is of green colour (meaning that there are both types of ions inside it). How does the colour of the mixture change, if $\ce{HCl(aq)}$ is added?

I know that, if a reactant is added to the equilibrium reaction, the chemical equilibrium is "moved" towards the products, vice versa.

However, the hydrochloric acid $\ce{HCl(aq)}$ is not a part of the equilibrium equation, so I don't know how it could in any way influence the chemical equilibrium. I need explanation for this problem.

## closed as off-topic by Mithoron, airhuff, Todd Minehardt, Tyberius, Jon CusterFeb 27 '18 at 15:04

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• HCl splits into H+ and Cl- in solution. – Tyberius Feb 26 '18 at 17:31