Dichloromethane tis used as a solvent as a paint remover, as a propellant in aerosols, and
as a process solvent in the manufacture af drugs. It is also used as a metal cleaning and

finishing solvent.

Trichloromethane It is employed as a solvent for fats, alkaloids, iodine and other

substances

Triodomethane It is usod as an antiseptic. Now, it has been replaced by some other

compounds because of its objectionable smel

Bul some compounds of this class are responsible for exposure of flora and fauna to more

‘and more of UV light which causes destruction to great extent

These are as follows

(i) Tetrachloromethane When carbon tetrachloride is released into the air il rises to the
aimosphere and depletes the ozone layer. Deplation of the ozone layer is believed to
increase human exposure to UV rays leading to increased skin cancer, eye diseases
and disorders, and possible disruption of the immune system, These UV rays cause
damage to plants, and reduction of plankton populations in the ocean's photic zone.

(i) Freons Freon-113 is tkely to remain in the air long enough to reach the upper
atomsphere. Here, it provides chlorine atoms which damage the ozone layer, Because
of this depletion UV rays enters in our atmosphere and become responsible for damage
to great extent

(ii), p= p-Dichlorodiphenyl trichloroethane (DDT)

DDT is not completely biodegradable. Instead, it gets deposited in fatty tissues. I
ingestion continues for a long time, DDT builds up within the animal and effect the
reproductive system.

To minimise the harmful impacts of these compounds j.e., freons, hydrolluorocarbons,
ftuorocarbons and hydrocarbons can be staight used to make refrigerants and
air-conditioning equipments. They are stable in the stratosphere and secure for flora and
fauna.