at equivalance point
CH3NH2 + HCl ------------------> CH3NH3^+Cl^-
0.1 xv         Â
0.1 xv
                    Â
0Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
before titration
0Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
0.1
xv             Â
after titration
CH3NH3^+Cl^ moles = 0.1 xv Â
CH3NH3^+Cl^ concentration = 0.1 xv  /total volume
[CH3NH3^+Cl^] = 0.1 v/2v
                     Â
C Â Â Â Â Â = 0.05M
salt is strong acid weak base type on hydrolysis of this
salt
pKb = -logKb= -log(5 x10^-4) = 3.30
pH= 7- 1/2 (pKb + logC)
   = 7- 1/2 (3.30 + log(0.05))
  pH = 6.00
