Question

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

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 :

$\tt Tb-100=0.512\times 0.743\times 2\\\\Tb-100=0.7608\\\\Tb=100.7608^OC$