Answer to Question #150372 in General Chemistry for Taavavarshini

Question

the pH value of an aqueous solution of hydrochloric acid is 2. what is the pH value of the solution after the addition of 10 g of sodium chloride?

Answer 1

Hydrochloric acid is a strong acid, it ionizes completely in aqueous solution. It is not a weak acid, therefore, no equilibrium is set up between unionized solute and the solution. NaCl is a neutral salt and it's addition to a solution of HCl has no effect on the pH of the solution, a phenomenon called "Common ion effect." This does not occur because HCl is a strong acid and ionizes completely in aqueous solution. Had it been a weak acid, the common ion Cl- will lower the ionization of the acid, causing the pH to reduce.

Therefore, the pH after the addition of 10g of NaCl to the solution still remains 2.(fairly constant)