A weak mono acidic base is 5% ionized in 0.01M solution. The hydroxide ion concentration in the solution is:

• A. 5 × 10⁻²
• B. 5 × 10⁻⁴
• C. 5 × 10⁻¹⁰
• D. 2 × 10⁻¹¹

To find the hydroxide ion concentration in a solution of a weak monoacidic base that is 5% ionized in a 0.01 M solution, we can follow these steps:

Step 1: Calculate the concentration of the ionized base

If the base is 5% ionized, we can calculate the concentration of the ionized base:

• Ionization percentage = 5%
• Concentration of the base = 0.01 M
• Ionized concentration = 5% of 0.01 M = 0.0005 M

Step 2: Determine the concentration of hydroxide ions

For a weak base, the concentration of hydroxide ions (OH^-) produced is equal to the concentration of the ionized base:

• OH^- concentration = 0.0005 M = 5 × 10^-4 M

Final Answer

The hydroxide ion concentration in the solution is 5 × 10^-4, which corresponds to option B.