The correct statement is:
A solution of potassium hydroxide will always have more OH⁻ ions than a solution of ammonia.
Here's the reasoning behind it:
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Potassium Hydroxide (KOH) is a strong base that completely dissociates in solution to give a high concentration of OH⁻ ions. For example, a 0.1 M solution of KOH will provide 0.1 M of OH⁻ ions.
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Ammonia (NH₃) is a weak base that partially dissociates in solution. The equilibrium for ammonia can be represented as: \[ \text{NH}_3 + \text{H}_2\text{O} \rightleftharpoons \text{NH}_4^+ + \text{OH}^- \] In a typical concentration, a 0.1 M solution of NH₃ does not generate as many OH⁻ ions compared to a strong base like KOH, because only a small fraction of NH₃ actually converts to NH₄⁺ and OH⁻.
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As a result, in comparison, a solution of potassium hydroxide will always contain a higher concentration of OH⁻ ions compared to a solution of ammonia at similar molar concentrations.
The other statements about pH and conductivity can vary based on concentration and specific conditions, so they can't definitively be claimed to be true in all cases. The last statement about solute concentration is misleading, as it does not take into account the molarity of the solutions being compared.