If HA, an acid, is 15 percent dissociated in a 2.00 molar solution, what is the Ka for the solution? A. 5.3 * 10-2 B. 6.4 * 10-3 C. 1.1 * 10-2 D. 1.2 * 10-2

Question

Chemistry

Zechariah Torres

19 December, 18:09

If HA, an acid, is 15 percent dissociated in a 2.00 molar solution, what is the Ka for the solution? A. 5.3 * 10-2 B. 6.4 * 10-3 C. 1.1 * 10-2 D. 1.2 * 10-2

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Answers (1)

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Amy Walsh · Answer 1

Answer: 0.3

Explanation:

We know that

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

And the acid is 15 % dissociated means that

[A-] / [HA] * 100 = 15%

So

[A-] / [HA] = 0.15

Then we know that [H+] = [A-] = 2 molar

Replacing we have

Ka = 2 molar * 0.15 = 0.3