The ionization constant of HA is 4.0e-4. Using the ice table what is the equilibrium concentration of HA in terms of its initial concentration and x?

Question

HA(aq) + H2O(l) = H3O^+^(aq) + A^-^(aq)

I 0.040M OM OM
C -X +x +x
E ? x x

I thought that to find the concentration you need to do 0.040-x=4.0e-4 but I am not sure if this is correct.

Answer 1

It is 0.04-x.

Answer 2

oh ok I see, thank you.