Estimate the change in the normal boiling temperature of an aqueous solution made by dissolving 12.6 g of phenol, C₆H₅OH, in 250 cm³ of water. The ebullioscopic constant of water is 0.51 K kg mol^-1. A) +0.27 K B) +0.068 K C) -1.6 K D) -0.65 K

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Quizplus · Accepted Answer

The boiling point elevation can be calculated using the formula ΔT = i * K_b * m, where i is the van't Hoff factor (1 for phenol), K_b is the ebullioscopic constant (0.51 K kg mol^-1), and m is the molality. Molality is calculated as moles of solute (12.6 g / 94.11 g/mol) divided by kg of solvent (0.250 kg). This gives ΔT ≈ 0.27 K.

Estimate the Change in the Normal Boiling Temperature of an Aqueous