Question

What is the boiling point (in C) of a 0.743 m

aqueous solution of KCI?
Enter your rounded answer with
3 decimal places.

Answer 1

The correct answer is 100.761.

Answer 2

The boiling point (in C) of a 0.743 m aqueous solution of KCI : 100.7608°C

Further explanation

Solutions from volatile substances have a higher boiling point and lower freezing points than the solvent

ΔTb = Tb solution - Tb solvent

ΔTb = boiling point elevation

`\large {\boxed {\boxed {\bold {\Delta Tb \: = \: Kb.m}}}`

For electrolyte solutions there is a van't Hoff factor = i

i = 1 + (n-1) α

n = number of ions from the electrolyte

α = degree of ionization, strong electrolyte α = 1, for non electrolytes i = 1

KCl⇒K⁺+Cl⁻⇒ electrolyte solution(2 ions K⁺ and Cl⁻), strong electrolyte α = 1

ΔTb=Kb.m.i

i = 1 + (n-1) α

i=1+(2-1).1=2

Kb for water (solvent) : 0.512 °C kg/mol

molal KCl = 0.743 m

The boiling point of solution :

`\tt Tb-100=0.512* 0.743* 2\\\\Tb-100=0.7608\\\\Tb=100.7608^OC`