Which of the following equimolar solutions has the highest conductivity?

Analyze the question: Conductivity of a solution depends on the concentration of mobile ions. For equimolar solutions (same concentration), the one that produces the most ions has the highest conductivity.

Concept:

• Strong electrolytes ionize completely and give many ions.
• Weak electrolytes ionize only slightly and give few ions.
• Also, H⁺ ions are very mobile, which increases conductivity further.

Analyze each option:

• A. H₂SO₄: a strong acid that ionizes almost completely. H₂SO₄ → 2H⁺ + SO₄²⁻ Each mole gives about 3 moles of ions, including highly mobile H⁺.
• B. NaOH: a strong base that ionizes completely. NaOH → Na⁺ + OH⁻ Each mole gives 2 moles of ions.
• C. H₂CO₃: a weak acid that ionizes only slightly, so few ions.
• D. CH₃COOH (written as CH₃COOH₄, a typo): a weak acid that ionizes only slightly, so few ions.

Compare: Strong electrolytes (A and B) beat weak ones (C and D). Between A and B, H₂SO₄ releases more ions per mole (about 3 versus 2), and H⁺ has a very high ionic mobility. So H₂SO₄ has the highest conductivity.

Answer: A. H₂SO₄(aq)

Tip: For "equimolar" conductivity questions, first pick out the strong electrolytes, then choose the one that gives the most ions per formula unit. Remember the strong acids: H₂SO₄, HCl and HNO₃. Weak acids such as ethanoic acid and carbonic acid always rank low.