The correct option is D 9.22
When only 100 mL of a 0.5 M CH3COONa(aq) is present. It will show simple salt hydrolysis.
The formula to calculate the pH of a salt of strong base and weak acid is :
pH=12(pKw+pKa+log C)pH=12(14+4.74+log0.5)pH=12(18.74−1+log 5)pH=12(18.44)pH=9.22