what is the acid dissociation constant of a weak acid if a concentration of 0.3 M gives a hydrogen ion concentration of 0.001M?

how do i do this??? i know you use the ka thing.

To determine the acid dissociation constant (Ka) of a weak acid, you need to use the equation for the dissociation of the acid in water.

For a general weak acid (HA), the dissociation equation is:

HA <--> H+ + A-

The Ka expression for this reaction is:

Ka = [H+][A-] / [HA]

Given that the concentration of the weak acid (HA) is 0.3 M and the hydrogen ion concentration ([H+]) is 0.001 M, we can substitute these values into the Ka expression:

Ka = (0.001 M)(0.001 M) / (0.3 M)

Now, to calculate the Ka, simply divide (0.001 M)(0.001 M) by 0.3 M:

Ka = 0.000001 M^2 / 0.3 M

Ka = 3.33 x 10^-6 M

So, the acid dissociation constant (Ka) of the weak acid is 3.33 x 10^-6 M.

To solve this problem, you used the Ka expression and substituted the given concentrations to calculate the value of Ka.

You don't USE the Ka thing, you SOLVE for the ka thing. Basically you have

HA ==> H^+ + A^-
Ka = (H^+)(A^-)/(HA) = Ka.
You know (H^+) and (A^-). (HA) = 0.3-0.001. Substitute and solve for Ka.