Elevation of boiling pointक्वथनांक का उन्नयनElevation of boiling point

NCERT Fig 1.7 · Class 12 Chemistry · Chapter 1 · interactive diagram

Parts and what they mean

• Vapour pressure curve of pure solvent (शुद्ध विलायक का वाष्प दाब वक्र) — It reaches 1.013 bar at Tb⁰ — the normal boiling point.
• Vapour pressure curve of solution (विलयन का वाष्प दाब वक्र) — Lies BELOW the solvent curve (lower vapour pressure at every temperature), so it needs a higher temperature to reach 1.013 bar.
• 1.013 bar (1 atm) line (1.013 bar (1 atm) रेखा) — A liquid boils when its vapour pressure equals the outside pressure.
• Tb⁰ — boiling point of pure solvent (Tb⁰ — शुद्ध विलायक का क्वथनांक) — For water, 373.15 K at 1.013 bar.
• Tb — boiling point of solution (Tb — विलयन का क्वथनांक) — Always higher than Tb⁰ for a non-volatile solute.
• ΔTb = Tb − Tb⁰ = Kb·m (ΔTb = Tb − Tb⁰ = Kb·m) — Elevation of boiling point; proportional to molality m. Kb (water) = 0.52 K kg mol⁻¹.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 1.7. Report a mistake