Incorrect statement on conductivity mechanisms

Steps:

• Electrical conductivity occurs via mobile charged particles like ions or electrons.
• Evaluate each choice against substance properties and charge carriers.
• Covalent molecular substances like glucose lack ions, so do not conduct.
• Ionic solids conduct via ions when mobile; metals via electrons.
• Acids conduct via dissociated ions, but check completeness for the example given.

Why B is correct:

• Sulfuric acid's second dissociation (HSO₄⁻ ⇌ H⁺ + SO₄²⁻) has Ka₂ = 0.012, so incomplete in dilute solution—not all ions form or are fully free to move.

Why the others are wrong:

• A: Glucose solutions do not conduct, as it is a non-electrolyte with no ions.
• C: Ionic compounds conduct via ion migration in molten/dissolved states, not electrons.
• D: Metals conduct via delocalized electrons; positive ions remain fixed in the lattice.

Final answer: B