Question

HCl and H2SO4 are strong acids. While their solutions are equimolar, they have different pH value as calculated in problem 10.1 and 10.3. Why they have different pH values?

Answer 1

Answer. 0.01M HCl pH value is 2 while that of 0.01M H2SO4 pH value is 1.7. Although both of these acids completely ionize, but the concentration of H+ is double in case of sulphuric acid than that of hydrochloric acid. Such as
      HCl (aq)        H+ (aq) + CI-
     H2SO4 (aq)           2 H+ (aq) + SO2-4(aq)
pH of an acid depends upon H+ concentration. As sulphuric acid produces more H+ ions its pH Value is less than that of hydrochloric acid.