Answer to Question 1
To produce carbon dioxide gas and aerate the candy.
Answer to Question 2
A supersaturated solution is one in which the concentration of sugar dissolved is greater than it would normally be at a certain temperature. It is prepared by heating a sugar solution to a high temperature and carefully cooling the concentrated sugar solution, without any jostling or agitation. Once supersaturated, the mixture is rapidly agitated to promote crystallization. This technique results in a candy with a smooth, creamy texture.