1. Determine whether the following hydroxide ion concentrations ([OH−]) correspond to acidic, basic, or neutral solutions by estimating their corresponding hydronium ion concentrations ([H3O+] using the ion product constant of water (Kw). Kw = [H3O+][OH−] = [1×10−7 M][1×10−7 M] = 1×10−14 M
Hydronium ion concentration [H3O+] Solution condition
Greater than 1×10−7 M Acidic
Equal to 1×10−7 M Neutral
Less than 1×10−7 M Basic
Drag the appropriate items to their respective bins.
1. [OH−] = 6×10−12 M
2. [OH−] = 9×10−9 M
3. [OH−] = 8×10−10 M
4. [OH−] = 7×10−13 M
5. [OH−] = 2×10−2 M
6. [OH−] = 9×10−4 M
7. [OH−] = 5×10−5 M
8. [OH−] = 1×10−7 M
A. Acidic
B. Neutral
C. Basic
2. A solution has [H3O+] = 5.2×10−5M . Use the ion product constant of water
Kw=[H3O+][OH−]
to find the [OH−] of the solution.
3. A solution has [OH−] = 2.7×10−2M . Use the ion product constant of water
Kw=[H3O+][OH−]
to find the [H3O+] of the solution.

Question 1.

1. [OH−] = 6×10−12 M  is less than 1 * 10⁻⁷, therefore is acidic.

2. [OH−] = 9×10−9 M  is less than 1 * 10⁻⁷, therefore is acidic.

3. [OH−] = 8×10−10 M  is less than 1 * 10⁻⁷, therefore is acidic.

4. [OH−] = 7×10−13 M  is less than 1 * 10⁻⁷, therefore is acidic.

5. [OH−] = 2×10−2 M  is greater than 1 * 10⁻⁷, therefore is basic.

6. [OH−] = 9×10−4 M  is greater than 1 * 10⁻⁷, therefore is basic.

7. [OH−] = 5×10−5 M  is greater than 1 * 10⁻⁷, therefore is basic.

8. [OH−] = 1×10−7 M  is equal to 1 * 10⁻⁷, therefore is neutral

Question 2:

[OH⁻] = 1.92 * 10⁻⁸ M

Question 3:

[H₃O⁺] = 3.70 * 10⁻¹¹ M

Explanation:

The ion product constant of water  Kw = [H₃O⁺][OH⁻] = 1 * 10⁻¹⁴ M² is a constant which gives the product of the concentrations of hydronium and hydroxide ions of dissociated pure water. The concentrations of the two ions are both equal to 1 * 10⁻⁷ in pure water.

A solution that has [OH⁻] greater than 1 * 10⁻⁷ is basic while one with [OH⁻] less than 1 * 10⁻⁷ is acidic.

1. [OH−] = 6×10−12 M  is less than 1 * 10⁻⁷, therefore is acidic.

2. [OH−] = 9×10−9 M  is less than 1 * 10⁻⁷, therefore is acidic.

3. [OH−] = 8×10−10 M  is less than 1 * 10⁻⁷, therefore is acidic.

4. [OH−] = 7×10−13 M  is less than 1 * 10⁻⁷, therefore is acidic.

5. [OH−] = 2×10−2 M  is greater than 1 * 10⁻⁷, therefore is basic.

6. [OH−] = 9×10−4 M  is greater than 1 * 10⁻⁷, therefore is basic.

7. [OH−] = 5×10−5 M  is greater than 1 * 10⁻⁷, therefore is basic.

8. [OH−] = 1×10−7 M  is equal to 1 * 10⁻⁷, therefore is neutral

Question 2:

Kw = [H₃O⁺][OH⁻] = 1 * 10⁻¹⁴ M²

[H₃O⁺][OH⁻] = 1 * 10⁻¹⁴ M²

[OH⁻] = 1 * 10⁻¹⁴ M²/ [H₃O⁺]

[OH⁻] = 1 * 10⁻¹⁴ M²/5.2*10⁻⁵ M

[OH⁻] = 1.92 * 10⁻⁸ M

Question 3:

Kw = [H₃O⁺][OH⁻] = 1 * 10⁻¹⁴ M²

[H₃O⁺][OH⁻] = 1 * 10⁻¹⁴

[H₃O⁺] = 1 * 10⁻¹⁴ M²/ [OH⁻]

[H₃O⁺] = 1 * 10⁻¹⁴ M²/ 2.7 * 10⁻² M

[H₃O⁺] = 3.70 * 10⁻¹¹ M