Arun
Last Activity: 6 Years ago
To solve we use formula, ΔTb = Kb × i × m
Where ΔTb is change in boiling temperature = 1°C or 1K
i is van’t Hoff factor =1 (solute does not dissociate )
Kb = molal boiling point elevation constant = 2.52 K kg/mol
m is molality of solute or m= moles of solute/mass of solvent in kg
we need molality in terms of molar mass
m= w2M2×w1
w2 = mass of solute = 6g
M2 = molar mass of solute
w1 = mass of solute in kg = 60 g or 0.06kg
Substituting in equation 1 and rearranging
We get answer as 253 gm/mol
M2 = i×Kb×w2ΔTb×w1
M2 = 1×2.52×101×0.1M2= 252g/mol
