Q. Which of the following gas is most harmful for ozone layer?
Answer: Chlorofluro-carbon
Notes: Chlorofluorocarbons (CFCs) are nontoxic, non-flammable chemicals containing atoms of carbon, chlorine, and fluorine. They are used in the manufacture of aerosol sprays, blowing agents for foams and packing materials, as solvents, and as refrigerants. Because CFCs contribute to?ozone?depletion in the upper atmosphere, the manufacture of such compounds has been phased out under the Montreal Protocol.