Q Though alcohol water mixture show positive deviation from Raoult's law then how this mixture is used to lower the freezing point of water.ie how this mixture is used as an antifreeze?

Hi

The term colligative agent may better describe the benefits of these compounds in warm climates, since they not only achieve freezing point depression in the winter when mixed with water, they coincidentally achieve boiling point elevation of water. Colligative agents are properly referred to as both antifreeze and "anti-boil" when used for both properties. The term engine coolant is widely used in the automotive industry, which covers its primary function of convective heat transfer.

The present invention relates to an antifreeze composition containing a water-soluble liquid alcohol and a corrosion inhibitor system comprising (a) a mixture of at least two aromatic or aliphatic dicarboxylic acids, or of at least two salts of the said acids, (b) at least one 1,3-diazole chosen from imidazole, benzimidazole, imidazoline and hydrocarbon derivatives thereof, and (c) at least one triazole compound. The aqueous fluids containing the said composition have excellent anticorrosive properties and heat stability over long periods of time, in particular when the fluids are used as heat transfer fluids at temperatures above 150° C.