Tag: combustion

Questions Related to combustion

A white solid $X$ reacts with dil.$HCl$ to give colourless gas which is used in fire extinguishers. The solid $X$ is:

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. $NaCl$

  2. $CH _2COONa$

  3. $Na _2CO _3$

  4. $NaHCO _3$

Show answer
Correct Option: D
Explanation:

Sodium bicarbonate can be used for fire extinguishers purpose as it releases carbon dioxide. 


The following reaction takes place: 

$ NaHC{ O } _{ 3 }(X)\ +\ HCl\ \rightarrow \ NaCl\ +\ C{ O } _{ 2 }\ +\ { H } _{ 2 }O $

Hence, the correct option is $\text{D}$

Fire extinguisher's containing $CO _2$ is the best extinguisher.

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. Because $CO _2$ being heavier than oxygen, covers the fire like a blanket

  2. Because $CO _2$ being heavier than oxygen, increase fire.

  3. Because $CO _2$ being leighter than oxygen, covers the fire like a blanket

  4. None of these

Show answer
Correct Option: A
Explanation:

For fires involving electrical equipment and inflammable material like petrol, carbon dioxide is the best extinguisher. Carbon dioxide being heavier than oxygen, covers the fire like a blanket. Since, the contact between the duel and oxygen is cut off, the fire is extinguished.

How carbon dioxide is stored in the house to extinguish fire?

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. It can store in the bottles

  2. It can store in the cylinders under high pressure

  3. It can store in canes

  4. It can not store in any form

Show answer
Correct Option: B
Explanation:

Carbon dioxide is being a gas can be store in cylinder's under high pressure like L.P.G.When released from the cylinder, carbon dioxide expands enormously in volume and cools down. So, it not only forms blanket around the fire, it also brings down the temperature of the fuel.

Why electrical equipment on burning do not extinguished fire by water? 

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. Water shows exothermic reaction with electrical equipment.

  2. Water conduct electricity with electrical equipment's.

  3. Water shows endothermic reaction.

  4. Water is a combustible substance.

Show answer
Correct Option: B
Explanation:

Water conducts electricity with electrical equipment's. Hence the area under water is developed with electricity. Therefore water is not used to the extinguished fire caused by electrical equipment.


Hence, the correct option is $B$

We cannot use a fire extinguisher which involves _____ as a extinguishing substance.

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. carbon dioxide

  2. baking soda

  3. foam

  4. petrol

Show answer
Correct Option: D
Explanation:

We cannot use petrol as a fire extinguisher, because petrol is a combustible liquid which on combustion produces a lot of heat energy. So petrol is not used to stop the fire.

Fire extinguishers contain $H _{2}SO _{4}$ and:

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. $NaHCO _{3}$ and $Na _{2}CO _{3}$

  2. $NaHCO _{3}$ solution

  3. $Na _{2}CO _{3}$

  4. $Ca _{2}CO _{3}$

Show answer
Correct Option: A

Some uses of chlorine and bromine are given.
Which is a use of bromine?

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. making bleaches for textiles and the the paper industry

  2. making CFC's

  3. making flame retardants and fire extinguishers

  4. making the polymer PVC

Show answer
Correct Option: C
Explanation:

In general, the stability of bromine in a typical flame retardant molecule means that the molecule can offer the highest activity as a flame active retardant, while also being cost effective.  The choice of flame retardant systems for any particular application depends on how the material decomposes in a fire, as well as the materials’ physical property. Brominated flame retardants, because they act in the flame, can be used in just about every application.

 $CO _2$ is able to control fires by disconnecting the supply of oxygen.

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Carbon dioxide is heavier than oxygen. Due to this, carbon dioxide forms a blanket around the burning material and makes a barrier between the burning material and oxygen. As oxygen supply is cutoff, it helps in extinguishing the fire.

When water is poured over burning wood, the fire goes off. This is because _________.

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. temperature of wood decreases

  2. temperature of water goes up

  3. molecules of water reacts with oxygen present in the flame

  4. the flame vapourises

Show answer
Correct Option: A
Explanation:

Water, when poured over fire absorbs large amount of heat and hence the temperature of wood falls below the ignition temperature. Thus the fire goes off.

Fire is extinguished by __________.

chemistry combustion extinguishing fire ways to control fire combustion, fuels and flame

  1. removing all combustible substance

  2. cutting off a supply of air

  3. cooling the burning substance

  4. all of the above

Show answer
Correct Option: D
Explanation:

Fire is extinguished by  :
(A) Removing all combustible substance. Fuel is one of the requirements for producing fire. In the absence of fuel, combustion will not occur.
(B) Cutting off a supply of air. Air (oxygen) is essential for combustion. In the absence of air, combustion will not occur.
(C) Cooling the burning substance. This reduces the temperature below its ignition temperature. The fire will not spread.