Which of the following would cause the percent ionization of a week acid to increase?

Question

Which of the following would cause the percent ionization of a week acid to increase? (A) Addition of a strong acid (B) Addition of a salt containing its conjugate base (C) Diluting with more water (D) The percent ionization of a week acid is a constant and cannot be increased.

Tardigrade Admin · Accepted Answer

Ka=(C α 2/1 - α ) . If α < 5 % , then 1-α =1 So Ka=Cα 2 or α =√(Ka/C) This shows that degree of ionization is inversely proportional to the square root of its molar concentration. Hence, α increases when solution is diluted with water.

Q. Which of the following would cause the percent ionization of a week acid to increase?

Addition of a strong acid

Addition of a salt containing its conjugate base

Diluting with more water

The percent ionization of a week acid is a constant and cannot be increased.

$K_{a} = \frac{C α ^{2}}{1 - α}$ .
If $α < 5%$ , then $1 - α = 1$
So $K_{a} = C α^{2}$
or $α = \frac{K _{a}}{C}$
This shows that degree of ionization is inversely proportional to the square root of its molar concentration. Hence, $α$ increases when solution is diluted with water.

Q. Which of the following would cause the percent ionization of a week acid to increase?

Addition of a strong acid

Addition of a salt containing its conjugate base

Diluting with more water

The percent ionization of a week acid is a constant and cannot be increased.

Ka​=1−αCα2​ . If α<5% , then 1−α=1 So Ka​=Cα2 or α=CKa​​​ This shows that degree of ionization is inversely proportional to the square root of its molar concentration. Hence, α increases when solution is diluted with water.

$K_{a} = \frac{C α ^{2}}{1 - α}$ .
If $α < 5%$ , then $1 - α = 1$
So $K_{a} = C α^{2}$
or $α = \frac{K _{a}}{C}$
This shows that degree of ionization is inversely proportional to the square root of its molar concentration. Hence, $α$ increases when solution is diluted with water.