The half-equivalence point of a titration occurs half way to the end point, where half of the analyte has reacted to form its conjugate, and the other half still remains unreacted. If 0.220 moles of a monoprotic weak acid (Ka = 1.8 Ã- 10-5) is titrated with NaOH, what is the pH of the solution at the half-equivalence point?

if 0.220 mole of the weak acid Ka is 1.8 *10^-5 is titrated with NAOH what is the PH of the solution at the half way equivalence point