Question

If the base-dissociation constant, Kb, for a substance is 4.3 x 10^–10, what does this tell you about Ka?

A) Ka = 2.3 x 10^–5
B) Ka = 1.0 x 10^–4
C) Ka = 2.3 x 10^2
D) Ka = 1.0 x 10^3

Answer 1

Ka*Kb=Kw=10^-14
Ka=10^-14/(4.3*10^-10) (at 25°C)
=2.3*10^-5 (A)

Answer 2

Answer: The correct answer is option (A)
`K_a=2.3* 10^(-5)`

Step-by-step explanation:

`K_b=4.3* 10^(-5)`

`K_w=1* 10^(-14)`

The relation between
`K_w,K_a and K_b` is given as:

`K_w=K_a* K_b`

`K_a=(K_w)/(K_b)=(1* 10^(-14))/(4.3* 10^(-10))`

`K_a=2.3* 10^(-5)`

Hence, the correct answer is option (A).