Answer:
-7.44°C
Explanation:
Calculate the molality of the solution. Use the density of the solvent(water) as a conversion factor in order to convert from millilitres of solvent to grams of solvent. Then convert grams into kilograms. Finally, use the molar mass of ethylene glycol as a conversion factor to convert from grams to moles of ethylene glycol.
m = 25.4 g C2H6O2/89.0 mL solv
= 4.6321 C10H8O
Compute the freezing-point depression.
ΔT_f=K_f*m ==> (1.86°C)*(3.9996 m)
=7.44°C
Compute the freezing point of the solution by subtracting the freezing-point depression to the freezing point of the pure solvent.
freezing point =0.0°C-ΔT_f
= -7.44°C