Which ones form buffer? Determine the pH of all solutions.?

Question

a)100.0ml of 0.010 M HCN and 200.0ml of .010 M NaC2H3O2

b)100.0ml of 0.010 HCl and 100.0ml of 0.020 M NH3

c)100.0ml of 0.020 M HOCl and 100.0ml of 0.010 M KOH

d)100.0ml of 0.010 M NaOH and 100.0ml of 0.010 M HC2H3O2

NH3: Ka=1.8 X 10^-5
HCN: Ka=6.2 X 10^-10
HC2H3O2: Ka = 1.8 X 10^-5
HOCl: Ka = 3.5 X 10^-8

VERY URGENT

Answer 1

Responders don't necessarily have Ka tables. Please supply them.