Chemistry Help? Initial Concentration?

Question

 

What is the initial concentration of HF that will give a 50% ionization? (Ka = 7.1 x 10-4) 

 

Answer 1

Step 1:

The percent ionization is 50 %.

k_a for HF is .

The chemical equation is .

The initial concentration of the [HF] is y M.

Let us consider change in the concentration:  , then .

Step 2:

Percentage ionization :

Step 3:

Acid ionization factor .

Substitute in the above equation.

The initial concentration of [HF] is M.

Solution:

The initial concentration of [HF] is M.