Experimentally, a solute is found to have a molar mass *lower* than its formula mass. This indicates the solute is:
ANon-electrolyte
BDissociating into ions/particles in solution
CInsoluble
DAssociating in solution
Answer & Solution
Correct answer: B. Dissociating into ions/particles in solution
Colligative properties detect **number of particles**. **Dissociation** → more particles → larger observed ΔT_b/ΔT_f than expected → calculated M_observed comes out *lower* than the formula mass. Association does the reverse.
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