Question

Antifreeze is ethylene glycol, C2H4(OH)2 and is made from ethylene which is produced from oil. It is miscible in water (i.e., dissolves in any proportion), does not dissociate in water, is toxic to drink (especially to dogs who like the sweet taste), but fortunately is biodegradable and at normal automobile operating temperatures, is not flammable. It can prevent freezing of the automobile cooling system down to -34oF and the advertisement says “winter - summer automobile coolant” — it also prevents boiling over in the summertime. For best protection, the directions read, “use a 50:50 mixture of ethylene glycol and water”. Wouldn't pure ethylene glycol do a better job of preventing freeze-up of your cooling system???? (Hint: the Fp of pure ethylene glycol is -11.5oC and the molal freezing point constant of water is 1.86 oC/molality) What is the freezing point temperature in oC of water if a 40.19 percent mixture (by mass) of ethylene glycol in water is used?

Answer 1