Question

Determine the change in the boiling point (ΔT_B) and Bp for a solution containing 0.328 moles of naphthalene (a nonvolatile, non-electrolyte compound) in 250. g of liquid benzene (Bp° = 80.1°C)? (K_b = 2.53˚ C/m)

answer choices

7.41 °C and 87.5 °C

7.41 °C and 72.7 °C

3.32 °C and 76.8 °C

4.31 °C and 0 °C

3.32 °C and 83.4 °C

Answer 1

0-328 Answer According to Raoult's law, elevation in boiling point (456) for a non-volatile, non-electrolyte compound dissolved in a solution- 4Tь Kb.c where kb is ebullioscopic constant of solvent and c is molality of solution. Here, C= m = 1.312 m Kb = 2.53 oc/m (2.53 °C/m) * (1•312 m) = 3.32 °C so a boiling point of solution (80.1 +3:32) oc = 83.4°C 0.250 " 4Tb Answer: 3032°c and 83.4°