Calculate the pH of a 0.10 M NaHX salt solution. Ka (H2X) = 2.1 x 10-2 Ka (HX-) = 4.5 x 10-8

Question

Can someone explain the steps to do this please?

Answer 1

The pH will be determined by the hydrolysis of the salt, NaX.

...........X^- + HOH ==> HX + OH^-
initial..0.10.............0....0
change....-x..............x.....x
equil....0.10-x...........x.....x

Kb for the salt = (Kw/Ka) = (x)(x)/(0.10-x)
Kw = 1E-14
Ka is Ka for HX, whatever that is. Solve for x = (OH^-), then convert to H^+ and to pH.