To calculate the pH of a solution containing 0.1 M hydrochloric acid HCl , we need to first determine the concentration of hydronium ions HO in the solution. HCl is a strong acid, which means it completely dissociates in water:HCl H + ClSince HCl completely dissociates, the concentration of H ions will be equal to the concentration of HCl, which is 0.1 M.Now, we can use the formula for pH:pH = -log[H]pH = -log 0.1 pH = 1So, the pH of the 0.1 M HCl solution is 1.