Properties of Aqueous Alkali Solutions

Steps:

• Alkali is an aqueous base, which increases OH- ion concentration.
• In basic solutions, pH exceeds 7 due to higher [OH-] than [H+].
• The ion with greatest concentration in alkali is OH-, as it defines the basic nature.
• Match these traits to the choice describing pH >7 and dominant OH-.

Why A is correct:

• By definition, aqueous alkalis have pH >7 and [OH-] > [H+], making OH- the ion with greatest concentration.

Why the others are wrong:

• B: In alkali, [OH-] exceeds [H+], so H+ is not dominant despite pH >7.
• C: pH <7 indicates acid, not alkali, though OH- is listed.
• D: pH <7 describes acid, where [H+] > [OH-], not alkali.

Final answer: A