Why does equilibrium shift to the left when AgNO3 is added to the equation Co(H20)6 (aq) + 4Cl- (aq) <---> CoCl4 (aq) + 6H2o(l)?

Answer 1

Adding Ag^+ ppts the Cl^- as AgCl thereby removing Cl^- from the equation. Therefore the reaction will try to replace the Cl^- that has been removed and it does that by the reverse (shift to the left) reaction.