Question

What should be done if the gas cylinder at home catches fire?
A.)Water should be sprinkled
B.)Sand, soil should be put at it
C.)Cylinder should be covered with wet blanket
D.)One should run away

Answer 1

Hint : A gas cylinder may catch fire due to several reasons. It can cause a disaster or put things on fire. Using water ($H_2O$) or sand ($SiO_2$) is not a good choice. At high temperature, they may decompose to give more oxygen which can worsen the condition.

Complete step-by-step answer:
A gas cylinder may catch fire due to our own carelessness. Usually, when there is a leakage in any gas cylinder, we get a very bad odour of Ethyl Mercaptan. This is to be taken very seriously. Now, there are two possible ways of disaster from a cylinder that has caught fire. They are ……
(i)The cylinder may get very heated due to the fire. So as a result of these, the temperature of the cylinder rises and the pressure of the gas present inside the cylinder also increases. Though there are pressure valves in the gas cylinder, it is never safe to let the temperature and pressure of the cylinder increase. This may lead to severe accidents.

(ii)When a gas cylinder catches fire, it actually means that there is some leakage in the cylinder. In most of the cases, it is seen that the leaked gas totally fills a closed room or some place where it is hard for the gas to get diffused in the external atmosphere. So when the air of the room becomes inflammable, a little ignition can cause an explosion.

In such a condition, sprinkling water or putting sand or soil on the cylinder will do no good.

In this place, the best option is to cover the cylinder with a wet blanket. Since the blanket is wet, it does not let the cylinder get heated to high temperature. Hence the pressure of the gas inside a cylinder is in control. Again the wet blanket will prevent any kind of farther leakage of gas.
So, option C is the correct answer.

Note:
When water is sprinkled on the cylinder, it may cool it down. But the leakage is not fixed. Similarly in case of sand or soil, the temperature is not controlled. So, the wet blanket is the correct choice.