no of moles of CH3COOH = molarity*volume in L
                                          Â
= 0.15*1 = 0.15 moles
no of moles of CH3COONa = molarity*volume in L
                                          Â
= 0.2*1 = 0.2 moles
PHÂ Â = PKa + log[CH3COONa]/[CH3COOH]
       = 4.74 +
log0.2/0.15
     = 4.74 + 0.1249  =
4.8649
By the addition of 0.05 moles of KOH
no of moles of CH3COOH = 0.15-0.05 = 0.1 moles
no of moles of CH3COONa  = 0.2+0.05 = 0.25 moles
PHÂ Â = PKa + log[CH3COONa]/[CH3COOH]
       = 4.74 +
log0.25/0.1
      = 4.74 + 0.3979 Â
= 5.1379
