Here we have an equilibrium between the complex ions
hexaaquacobalt(II)
and
tetrachlorocobaltate(II)
Write the equation of this equilibrium!
Why does the addition of hydrochloric acid shift she equilibrium to the right?
According to the principle of the Châtelier, the addition of a reactant tends to eliminate some of this reactant to form more products.
Why does the addition of water shift the equilibrium to the left?
According to the principle of the Chatelier, the addition of a product tends to remove a portion of this product to reform the reactants.