Question

The Ka of an acid is 1.3 mc020-1.jpg 10–7. Based on the Ka and its relationship with Kw, what is the value of Kb?
Use mc020-2.jpg.
1.3 mc020-3.jpg 10–21
7.7 mc020-4.jpg 10–15
1.3 mc020-5.jpg 10–14
7.7 mc020-6.jpg 10–8

Answer 1

Kb = Kw/Ka. Using Kw = 1.0×10^−14 and Ka = 1.3×10^−7:

Kb = (1.0×10^−14)/(1.3×10^−7) = (1/1.3)×10^−7 ≈ 7.7×10^−8.

So the correct choice is 7.7 × 10^−8.