Answer:
Kb → 1.56 °C / m
Explanation:
This is all about boiling point elevation, the colligative property that shows that boiling point for a solution is higher than boiling point of pure solvent.
This is the formula: ΔT = Kb . m . i
where i is the Van't Hoff factor (ions dissolved in solution). As these are organic compounds, we assume they are non electrolytic,
m is molality (mol of solute / 1kg of solvent)
Kb is our unknown. The value for ebulloscopic constant, it is specific for each solvent.
ΔT = T° boiling from solution - T° boiling from solute
First of all, let's determine the moles of solute.
Mass / Molar mass → 32.5 g/ 113.45 g/mol = 0.286 mol
Molality is mol of solute/ 1 kg of solvent
We must convert the mass from g to kg
195g . 1kg /1000 = 0.195 kg
Molality = 0.286 mol / 0.195 kg = 1.47 m
Let's replace the values in the formula
133.30 °C - 131°C = Kb . 1.47m .1
2.30°C / 1.47 m = Kb → 1.56 °C / m
, and
.