To calculate the pH of a solution with a concentration of 0.1 M hydrochloric acid HCl , we can use the formula:pH = -log10[H+]Hydrochloric acid is a strong acid, meaning it dissociates completely in water to form H+ and Cl- ions. Therefore, the concentration of H+ ions in the solution is equal to the concentration of the HCl, which is 0.1 M.Now, we can plug this value into the formula:pH = -log10 0.1 pH = 1So, the pH of a 0.1 M hydrochloric acid solution is 1.