Question

what is dry ice ?? how it is prepare

Answer 1

dry ice , sometimes referred to as "cardice" (chiefly by British chemists), is the solid form of carbon dioxide. It is used primarily as a cooling agent. Its advantages include lower temperature than that of water ice and not leaving any residue (other than incidental frost from moisture in the atmosphere).

Answer 2

Dry ice is solid state of carbon dioxide
CO2 is pressurised and cooled to form dry ice

It's sometimes referred to as" cardice "