number of moles of sodium Lactate = M*V
                                  Â
= 1M * 0.2 L
                                  Â
= 0.2 mol
mass of sodium lactate = MW * number of
moles
                      Â
= 112 g/mol * 0.2 mol
                      Â
= 22.4 g
Answer: 22.4 g
pKa = -log Ka
3.86 = -log Ka
Ka= 1.38*10^-4
Kb of lactate = 10^-14 / (1.38*10^-4) =
7.244*10^-11
lactate ion + H2O = lactic acid + OH-
1.0
MÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â
   0
         0       Â
1.0-x                  Â
x        Â
x
Kb = x*x / (1.0-x)
7.244*10^-11 Â Â = x^2 /1
x = 8.551*10^-6 M
So,
[OH-] = 8.551*10^-6 M
pOH = -log [OH-]
     = -log
(8.551*10^-6)
     = 5.07
pH = 14 – pOH
   = 14 – 5.07
   = 8.93
Answer: 8.93
