Question

The fire extinguisher ‘Pyrene’ contains:
(A) Carbon dioxide
(B) Carbon disulphide
(C) Carbon tetrachloride
(D) Chloroform

Answer 1

Carbon tetrachloride, $CC{l_4}$ , which remains stable under fire conditions and is inflammable is generally used in fire extinguishers. Its boiling point is $76.7^\circ C$ . While its melting point is $22.4^\circ C$ . It is an organic chemical in nature.

Complete answer:
Fire extinguisher ‘Pyrene’ contains carbon tetrachloride $CC{l_4}$ . When carbon tetrachloride is heated, it decomposes and emits fumes of toxic phosgene $(COC{l_2})$ as well as hydrogen chloride $(HCl)$ . The dense layer of carbon tetrachloride vapours forms a protective layer on the burning place or burning object and blocks the supply of oxygen or air.
It is also used in large quantities for manufacturing refrigerants and propellants for aerosol cans. It is also used in the synthesis of chlorofluorocarbons and other pharmaceutical manufacturing.
Scientific study provides evidence that exposure to carbon tetrachloride causes liver cancer in humans. If inhaled, it causes dizziness, lightheadedness, nausea and vomiting, which might result in permanent damage to nerve cells. These effects can also lead rapidly to stupor, coma, unconsciousness or death. Exposure to $CC{l_4}$ can make the heartbeat irregularly or stop. It can also cause irritation to the eyes on contact. If carbon tetrachloride is released into the air, it rises to the atmosphere and depletes the ozone layer. Due to its environmental concerns and its poisonous nature, its use has gradually declined after $1960's$ .
Hence, the correct option is C.

Note:
Carbon tetrachloride can also be used as a degreasing agent in industries and as cleaning agent and spot remover at homes. However, it is generally avoided because of its poisonous nature. $CC{l_4}$ is insoluble in water and has a characteristic odour.