Dry ice, also referred to as "cardice" is the solid form of carbon dioxide.
Dry ice is colorless, non-flammable, with a sour zesty odor, and can lower the pH of a solution when dissolved in water, forming carbonic acid.
Prolonged exposure to dry ice can cause severe skin damage through frostbite. Dry ice should only be exposed to open air in a well-ventilated environment and should be used with insulated gloves to avoid frostbite.
i) Primarily used as a cooling agent
ii) for preserving frozen foods where mechaical cooling is unavailable
iii) for loosening asphalt floor tiles
iv) for freezing water in valveless pipes to enable repairing