Answer
See the answer below.
Work Step by Step
KNO3 solution:
For 1kg of the solution:
Number of moles of solute: $100\ g\div101.10\ g/mol=0.989\ mol$
Molality: $0.989\ mol\div 0.9\ kg=1.099\ molal$
The number of moles of solvent: $900\ g\div 18.02\ g/mol=49.96\ mol$
Mole fraction: $0.989\div(0.989+49.96)=0.019$
Acetic acid solution:
For 1kg of the solvent:
Number of moles of solute: $0.0183\ molal\times1\ kg=0.0183\ mol$
Mass of solute: $0.0183\ mol\times 60.05\ g/mol=1.10\ g$
Weight percent: $1.10\div(1.10+1000)\times100\%=0.11\%$
Number of moles of solvent: $1000\ g\div 18.02\ g/mol=55.49\ mol$
Mole fraction: $0.0183\div(0.0183+55.49)=0.00033$
Ethylene glycol solution:
For 1kg of the solution:
Number of moles of solute: $180\ g\div62.07\ g/mol=2.90\ mol$
Molality: $2.90\ mol\div 0.82\ kg=3.54\ molal$
The number of moles of solvent: $820\ g\div 18.02\ g/mol=45.52\ mol$
Mole fraction: $2.90\div(2.90+45.52)=0.06$
