Question

At 25°C the concentration of each of H⁺ and OH⁻ ions in pure water is about mole/liter.

Options

A
10-6
B
10-7
C
10-9
D
10-14

Explanation

The correct answer is Option B: 10^-7. In pure water, at 25°C, the concentration of both H⁺ and OH⁻ ions is about 10^-7 moles per liter. This balance of ions is essential for the unique properties of water, such as its ability to act as a solvent and participate in various biochemical reactions. Options A, C, and D are incorrect as they do not represent the correct concentration of ions in pure water at the given conditions.

This option is incorrect. In pure water at 25°C, the concentration of both H⁺ and OH⁻ ions is approximately 10^-7 moles per liter.

This statement is correct because pure water naturally dissociates into equal amounts of H⁺ and OH⁻ ions.

At 25°C, this self-ionization reaches a point where each ion has a concentration of about 10⁻⁷ mol/L.

These equal concentrations keep pure water neutral.

It’s this balance that gives water a pH of 7 under standard conditions.

This option is incorrect. In pure water at 25°C, the concentration of both H⁺ and OH⁻ H+ and OH- ions is approximately 10^-7 moles per liter.

This option is incorrect.

Pure water self-ionizes so [H⁺] = [OH⁻] at equilibrium.

At 25°C those concentrations are about 1×10⁻⁷ mol·L⁻¹, giving pH 7.