Calcium chloride is in the salt family. It is used extensively in colder climates as a compound that is spread on sidewalks and driveways. As the salt ionizes, or splits in two, it reacts with the water, forming a dilute solution of hydrochloric acid, releasing heat at the same time. Heat is good on cold sidewalks, as you can imagine. Calcium chloride also reacts with sodium bicarbonate to release carbon dioxide gas.