colligative: boiling point elevation

Question

Which parameter affects boiling point elevation (ΔTb) directly?

RankGuru · Accepted Answer

1. **The Formula**: $\Delta T_b = K_b 	imes m 	imes i$.
2. **Breakdown**:
   - $\Delta T_b$: Elevation in boiling point.
   - $K_b$: Ebullioscopic constant (solvent property).
   - **$m$**: **Molality** (concentration of solute particles per kg of solvent).
   - $i$: van't Hoff factor (degree of dissociation/association).
3. **Colligative Property**: These properties depend only on the **number** of solute particles, not their identity ($color$, $pH$, $reactive$ $nature$).
4. **Mechanism**: Non-volatile solute particles block the escape of solvent molecules, lowering vapor pressure. Thus, more heat is needed to reach atmospheric pressure, raising the boiling point proportional to the **molality**.

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colligative: boiling point elevation

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