It is dry ice. Dry ice is solid carbon dioxide, which is condensed into colorless liquid under the pressure of 6250.5498 kPa and solidified rapidly under low pressure. After adding water, white gas will slowly emerge, and the smoke is mysterious.

The use of dry ice on the dining table is actually used to decorate dishes and create an illusory "fairy spirit". Special plates are usually needed on the dining table, because dry ice can't be in direct contact with dishes, otherwise it will make the taste of dishes worse.

This special plate will have a compartment with dry ice at the bottom, a plate on the top and some small holes on the side, which is convenient for pouring boiling water to melt the dry ice, thus generating "fairy gas" and emerging through the small holes, thus becoming a very popular dry ice cigarette tray in hotels.

Dry ice is the solid form of carbon dioxide.

Under normal circumstances, CO2 is a colorless and odorless gas, which naturally exists in the air, although the content of CO2 in the air is relatively small (the volume ratio is about 0. 03%), but it is one of the most important gases we know.

Dry ice is highly volatile, and sublimates into non-toxic and odorless gas carbon dioxide, which is 1000 times larger than the solid area, so dry ice cannot be stored in containers with good sealing performance and small volume, and it is easy to explode. It is safe to put dry ice in a well-ventilated place and let the gas generated by dry ice volatilization be released.