Question

C2H6O2 is infinitely miscible (soluble) in water. Ethylene glycol is a nonelectrolyte that is used as antifreeze. What is the lowest possible melting point for engine coolant that is 27.1 % (by mass) ethylene glycol

Answer 1

-11.13 Degree Celsius

Step-by-step explanation:

Here

Kf for H20 is 1.86 C/m

Mass of ethylene glycol = 27.1/100 * 100 = 27.1 grams

Number of moles of ethylene in 30 grams of ethylene = 27.1 g/molar mass of ethylene glycol = 27.1/62.07 = 0.4366 mol

Mass of water = 100 – 27.1 = 72.9 grams

Molality = Moles/Mass of water in Kg = 0.4366 /0.0729 = 5.989 m

Melting Point Depression = Kf * Molality = 1.86 *5.989 = 11.13 deg C

Melting point of solution = Melting point of water - Melting Point Depression

= 0 – 11.13 = -11.13 Degree Celsius