Tag: extinguishing fire

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Questions Related to extinguishing fire

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

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

  1. $NaCl$
  2. $CH _2COONa$
  3. $Na _2CO _3$
  4. $NaHCO _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
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 $\text{D}$

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

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  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
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

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

  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.
Reveal answer Fill a bubble to check yourself
B Correct answer
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 $B$

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

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

  1. $NaHCO _{3}$ and $Na _{2}CO _{3}$
  2. $NaHCO _{3}$ solution
  3. $Na _{2}CO _{3}$
  4. $Ca _{2}CO _{3}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Soda-acid fire extinguishers work by reacting sulfuric acid with sodium bicarbonate (NaHCO3) to produce carbon dioxide gas, which displaces oxygen and puts out the fire. Option A is the standard chemical composition for this type of extinguisher.

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

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

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Fire is extinguished by __________.

  1. removing all combustible substance

  2. cutting off a supply of air

  3. cooling the burning substance

  4. all of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
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.