Raising agents for baking

A raising agent or leavening agent is any one of a number of substances used in dough and batters that causes a foaming action that lightens and softens the finished product. Formation of carbon dioxide is induced by chemical agents reacting with moisture, heat, acidity, or other triggers.

Types of leavening agents:
Mechanical agents 
•Water
•Atmosphere

 Biological 
•Yeast

Chemical 
•Baking powder
•Baking soda
•Ammonium bicarbonate

Chemical leavening involves the action of an acid on bicarbonate to release carbon dioxide gas for aeration of a dough or batter during mixing and baking. The aeration provides a light, porous cell structure, fine grain, and a texture with desirable appearance along with palatability to baked goods.

The main three chemical leaveners used in baking are:
•Baking Powder
•Baking Soda
•Ammonium Carbonate

Baking powder 
•Baking powder is a mixture of bread soda and an acid
•When moistened by eggs or milk carbon dioxide is produced
•The carbon dioxide expands and rises when heated, raising the dough

All raising agents (leaveners) work on the same principal, be it Chemical, Mechanical or Natural. Gasses expand, push up against a structure, you get rise, which is fixed by the heat of the oven. It is by using ingredients and baking techniques in the correct manner which ensures success baking.
Raising agents for baking