Question

Which of the following solutions has the HIGHEST hydroxide-ion concentration?a) 0.1 M HClb) 0.1 M H2SOc) a buffer solution with pH= 5d) a buffer solution with pOH= 12e) NONE

Answer 1

Answer:

c) a buffer solution with pH= 5

Explanation:

The equation of hydrolisis of water is:

1x10⁻¹⁴ = [H⁺] [OH⁻]

That means if we know [H⁺] we can find hydroxide-ion concentration and vice versa.

a) HCl 0.1M = [H⁺] = 0.1M;

1x10⁻¹⁴ / [H⁺]

1x10⁻¹⁴/ 0.1M = [OH⁻]

1x10⁻¹³M = [OH⁻] hydroxide- ion concentration.

b) 0.1M H₂SO₄ = 0.2M [H⁺]

1x10⁻¹⁴/ 0.2M = [OH⁻]

5x10⁻¹⁴M = [OH⁻]

c) pH = 5.

[H⁺] = 1x10⁻⁵M

1x10⁻¹⁴/ 1x10⁻⁵M = [OH⁻]

1x10⁻⁹M = [OH⁻]

d) pOH = 12.

[OH⁻] = 1x10⁻¹²M

That means risht answer is:

c) a buffer solution with pH= 5