Question

How will the concentration of H+ and OH− ions change when a substance with a pH 11.4 is added to water?

Answer 1

Answer is: H+ will increase and OH− will decrease.

pH = 11.4.

pH = -log[H+].

[H+] = 10∧(-pH).

[H+] = 10∧(-11.4).

[H+] = 4·10⁻¹² mol/L.

[H+] · [OH-] = 1·10⁻¹⁴ mol²/dm⁶.

[OH-] = 0.0025 mol/L.

pH value (potential of hydrogen - [H+]) is a logarithmic scale that specify the acidity or basicity of an aqueous solution.

When pH is greater than seven, aqueous solution is basic, below seven is acidic and when pH is equal seven, solution is neutral.

Answer 2

Answer : The correct option is, $H^+$ will decrease and $OH^-$ will increase

Explanation :

As we know that the water is made up of the $H^+$ and $OH^-$ ions. When a substance with a pH 11.4 that means the solution is basic in nature is added to water, the concentration of $OH^-$ ions increase and the concentration of $H^+$ ions decreases.

In the basic solution, the concentration of $OH^-$ ions are more than the concentration of $H^+$ ions. So, when a base is added to the water the more $OH^-$ ions dissociates in the water as compared to the $H^+$ ions.

Hence, the correct option is, $H^+$ will decrease and $OH^-$ will increase