To calculate the pH of a 0.05 M solution of hydrochloric acid HCl , we need to use the formula:pH = -log10[H+]Hydrochloric acid is a strong acid, which means it completely dissociates in water. Therefore, the concentration of hydrogen ions [H+] in the solution will be equal to the concentration of the HCl.[H+] = 0.05 MNow, we can plug this value into the pH formula:pH = -log10 0.05 pH 1.3So, the pH of a 0.05 M solution of hydrochloric acid is approximately 1.3.