The pH of an aqueous solution at 25∘C having 0.1 M NaOH and 0.3 M to acetic acid (pKa = 4.76) would be nearly
4.45
pH = pKa−log[acid][salt]
0.1 M NaOH will react with acid to form 0.1 M CH3COONa and therefore 0.3 CH3COOH will be reduced to 0.2 M.
pH = 4.76 – log0.20.1 = 4.45