Change in concentration Procedure Observation Initial color of the CuSO4 solution light blue Color of the solution after NH3 is added dark violet Color of the solution after adding HCI light blue /clear a) Write the equation for the equilibrium is established (net ionic reaction) when CuSO4 is mixed with NH3: + at ( dy & spi Cu 2+ (aq) + 4NH₃ lag) [Cu(NH3)4] (aq) b) Which direction did the equilibrium shift when NH3 was added to CuSO4? Describe the type of stress this applied to the equilibrium in equation (a) and how the observed shift relieves that stress.