Weak acids partially ionize in solution

Steps:

• Recall that acids are classified as strong or weak based on ionization in water.
• Strong acids fully dissociate into ions, while weak acids only partially do so.
• Ethanoic acid (CH₃COOH) has the equilibrium: CH₃COOH ⇌ CH₃COO⁻ + H⁺, showing incomplete dissociation.
• This partial ionization defines it as weak, unlike strong acids like HCl.

Why C is correct:

• Weak acids are defined by their low degree of dissociation in water, producing few H⁺ ions, as per the equilibrium constant Ka < 1 for ethanoic acid.

Why the others are wrong:

• A: Being organic does not determine acid strength; some organic acids are strong.
• B: Poor conductivity results from low ionization, but it's not the definition of weakness.
• D: Reaction with metals depends on acid strength but isn't the core reason for being weak.

Final answer: C