To calculate the pH of a 0.1 M solution of hydrochloric acid HCl , we can use the formula:pH = -log10[H+]Hydrochloric acid is a strong acid, which means it completely dissociates in water:HCl H+ + Cl-In a 0.1 M solution of HCl, the concentration of H+ ions is also 0.1 M. Now we can use the formula to calculate the pH:pH = -log10 0.1 pH = - -1 pH = 1The pH level of a 0.1 M solution of hydrochloric acid is 1.