Question

Which of the following is the strongest acid?

Group of answer choices

hypoiodous acid (molar mass: 143.89 g/mol; K_a = 2.0 x 10^-11)

acetic acid (molar mass: 60.05 g/mol; K_a = 1.8 x 10^-5)

nitrous acid (molar mass: 47.01 g/mol; K_a = 4.6 x 10^-4)

chloroacetic acid (molar mass: 94.49 g/mol; K_a = 1.4 x 10^-3)

chlorous acid (molar mass: 68.46 g/mol; K_a = 1.1 x 10^-2)

What is the concentration of [OH^-] in pure water if K_w = 6.97 x 10^-15?

Group of answer choices

8.35 x 10^-8 M

2.70 x 10^-7 M

9.42 x 10^-8 M

1.46 x 10^-7 M

3.01 x 10^-7 M

Answer 1

1)

Ka is acid dissociation constant.

Greater value of Ka implies, stronger acid.

ka is largest for chlorous acid

So, this is strongest

Answer: chlorous acid

2)

Kw = [H+] [OH-]

Since water is neutral, [H+] = [OH-]

So,

Kw = [OH-][OH-]

Kw = [OH-]^2

6.97*10^-15 = [OH-]^2

[OH-] = 8.35*10^-8 M

Answer: 8.35*10^-8 M