Name the law or principle to which the following observations conform :
(1) When water is added to a 1.0 M aqueous solution of acetic acid, the number of hydrogen ion (`H^+`) increases.
(2) When 9650 coulombs of electricity is passed through a solution of copper sulphate, 3.175 g of copper is deposited on the cathode.(at. wt. of Cu = 63.5).
(3) When ammonium chloride is added to a solution of ammonium hydroxide, the concentration of hydroxyl ions decreases.