Question
An unknown volume and unknown concentration of a weak acid HX is titrated with NaOH of unknown concentration. After addition of 10.0 cm3 of the NaOH solution, the pH of the solution is 5.7. After the addition of 20.0 cm3 of the NaOH solution, the pH is 6.3. Calculate the pKa of the weak acid, HX. (Given: log2 = 0.3, log = 0.5)