What is the boiling point of a solution of 11.0 g of lactose (C₁₂H₂₂O₁₁)in 145.0g of water? (K_b (H₂O)= 0.52 °C/m) A)0.1°C B)99.9 °C C)100.1°C D)102.2 °C E)105.7 °C

Question

Quizplus · Accepted Answer

First, we need to calculate the molality of the lactose solution:

molality = moles of solute / mass of solvent in kg
moles of lactose = 11.0 g / 342.3 g/mol = 0.032 moles
mass of solvent = 145.0 g / 1000 = 0.145 kg
molality = 0.032 / 0.145 = 0.221 mol/kg

Next, we can use the boiling point elevation equation to calculate the increase in boiling point:

ΔTb = Kb * molality
ΔTb = 0.52 °C/m * 0.221 mol/kg = 0.115 °C

Finally, we add the increase in boiling point to the normal boiling point of water (100 °C) to get the boiling point of the lactose solution:

boiling point = 100.0 °C + 0.115 °C = 100.1 °C

Therefore, the correct answer is choice C, 100.1°C.

What Is the Boiling Point of a Solution of 11