This document discusses several important chemical compounds including common salt, sodium hydroxide, chlorine, hydrogen, baking soda, washing soda, and plaster of Paris. It describes their chemical formulas, methods of production, and key uses. For example, it explains that sodium hydroxide is produced through the chloralkali process of electrolyzing salt water to produce chlorine, hydrogen, and sodium hydroxide. Sodium hydroxide then has various industrial and domestic uses such as for making soap.