Ishwar S. answered 04/23/21
University Professor - General and Organic Chemistry
This question demonstrates the colligative properties of a solution. Use the equation, ΔTb = Kb x molality to solve this problem.
ΔTb = Tb solution - Tb solvent
Solute = KBr
Solvent = H2O
Tb of solvent = 100.00 °C
Kb for water = 0.512 °C m-1
molality (m) = moles of solute / kg of solvent
m = 0.75 mol / 1.0 kg = 0.75 m
Enter the values from above in the equation,
ΔTb = Kb x m
Tb solution - 100.00 = 0.512 x 0.75
Tb solution = 100.00 + 0.384 = 100.38 °C