After titration we can see that 4mmol of CH3COOH and 2mmol of CH3COONa are present. Final Concentration =Moles Total Volume Total Volume =30+10=40mL [CH3COOH]=440M [CH3COONa]=240M An acidic buffer is formed. So, pH=pKa+log([CH3COONa][CH3COOH])pH=4.74+log⎛⎝240440⎞⎠pH=4.74+log(12)=4.74−0.3pH=4.44