Chemistry Math Question

Question

If equal volumes of 0.28 M acetic acid and 0.18 M sodium hydroxide are mixed, what is the pH of the resulting solution? The pK_a of acetic acid is 4.75

Answer 1

HAc + OH^- === > Ac^- + H₂O

o.28...0.18..............0..........Initual

-0.18...-0.18..........+0.18.....Change

0.10......0...............0.28.....Equilibrium

pK = pKa + log [Ac] /[HAc]

pH =4.75 + log (0.28/0.20)

pH = 4.75 + 0.45 = 5.2