Find the pH of a strong acid
To find the pH of .2M HClaq, first realize that HCl is a strong acid. That means it completely dissociates into H+ and Cl-. The concentration of H+ is there .2M. Thus, the pH is: - log (.2) = .7
Find the pH of a weak base
Ti find the pH of .2M NaOHaq, first realize that NaOH is a strong base. That means it completely dissociates into OH- and Na+. The concentration of OH- is .2M. Therefore, the pOH is: - log (.2) = .7 & the pH will be: 14-.7 = 13.3