question

give reasons :

 a decrease in temperature is observed on mixing ethanol and acetone.
 potassium chloride solution freezes at a lower temperature than water.

 

 

 

 

 

 

 

 

(a) ethanol & acetone forms a non-ideal solution showing positive deviation which is accompanied by absorption of heat and a slight increase in volume, whats why a decrease in temperature is observed.

(b) potassium chloride solution freezes at a lower temperature than water because the vapour pressure of the solution isless than that of pure solvent, hence the freezing point decreases.