Question

If the K_a of a monoprotic weak acid is 8.2

Answer 1

                      HA <-----> A-   +        H+
Initial:           0.28    0                 0
Change:          -x                 +x              +x
Final:           0.28-x                x x

Ka= x^2/0.28-x,

If 0.28 is greater than 100 Ka, we can approximate by ignoring the x subtracted from 0.28 and that is the case overhere.

Ka= x^2/0.28

8.2