In dehydrohalogenation of 2-chlorobutane, but-2-ene (disubstituted alkene) is the preferred product because it is formed faster than but-1-ene (monosubstituted alkene) which is in accordance with Saytzeff rule.
environmental effect of CFC:
1. Chloroflurocarbons are responsible for ozone depletion in stratosphere.
2. Regular large inhalation of freons results in breathing problems, organ damage, loss of consciousness.
use of CFC:
1. They are used as refrigerants in fridges and air conditioning.
2. They are used as propellants in aerosol and solvents.
3. They are used as blowing agents in making foams and packing materials.