PLEASE SHOW ALL WORK/ EXPLAIN DQuestion 7 1.25 pts tert-Butyl alcohol is a solve

Question

PLEASE SHOW ALL WORK/ EXPLAIN

DQuestion 7 1.25 pts tert-Butyl alcohol is a solvent with a Kf of 9.10 °C/m and a freezing point of 25.5 oC. When 0.807 g of an unknown colorless nonelectrolyte liquid was dissolved in 11.6 g of tert-butyl alcohol, the solution froze at 17.0 °C. Which of the following is most likely the identity of this unknown liquid? ethylene glycol (molar mass-62.07 g/mol) 1-octanol (molar mass 130.22 g/mol) slycerol (molar mass 92.09 g/mol) 2-pentanone (molar mass 86.13 g/mol) 1-butanol (molar mass 74.12 g/mol)

Explanation / Answer

delta Tf = 25.5 oC - 17.0 oC

= 8.5 oC

we have below equation to be used:

delta Tf = Kf*mb

8.5 = 9.1 *mb

mb= 0.9341 molal

mass of solvent = 11.6 g

= 1.16*10^-2 kg [using conversion 1 Kg = 1000 g]

we have below equation to be used:

number of mol,

n = Molality * mass of solvent in Kg

= (0.9341 mol/Kg)*(0.0116 Kg)

= 1.084*10^-2 mol

mass of solute = 0.807 g

we have below equation to be used:

number of mol = mass / molar mass

1.084*10^-2 mol = (0.807 g)/molar mass

molar mass = 74.48 g/mol

Answer: 1-butanol

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