Combustion, Flame and Fuels

Which gas is formed as a result of incomplete combustion?

• Carbon dioxide

• Coal gas

• Nitrogen monoxide

• Carbon monoxide

An ideal fuel must have (note - there can be more than one correct answer)

• high calorific value

• low ignition temperature

• moderate ignition temperature

• moderate calorific value

for combustion to take place, which of the following is NOT used?

• a supporter of combustion

• a non combustible substance

• a combustible substance

• heating until the ignition temperature

Which zone of the flame undergoes complete combustion?

• Non - luminous zone

• Luminous zone

• Middle zone

• Dark zone

A fire has occured in the factory due to a faulty electrical outlet. Choose the correct extinguisher to put out the fire.

• Soda acid fire extinguisher

• Carbon dioxide fire extinguisher

• Nitrogen fire extinguisher

• Carbon monoxide fire extinguisher

What gases are NOT released when fuels are burnt? (more than one answer)

• Carbon monoxide

• Carbon dioxide

• Oxygen

• Methane

• Oxides of sulphur and nitrogen

given below are the calorific values and the ignition temperature of fuels X, Y and Z. Choose the best fuel

• Fuel X

  Calorific value - 45,000 kJ/kg

  Ignition temp - 350 ° C

• Fuel Y

  Calorific value - 35,000 kJ/kg

  Ignition temp - 750 ° C

• Fuel Z

  Calorific value - 100,000 kJ/kg

  Ignition temp - 1000 ° C

In a laboratory, sodium metal was kept idle. Immediately, without any external igniton, a fire had occured.

Reena had concluded that this was rapid combustion as it occured quickly.

John had concluded that this was spontaneous combustion as there was no external ignition.

Who is correct?

• Reena

• John

Which zone of a flame is yellow - orangish in color?

• Dark zone

• Middle zone

• Outermost zone

A kitchen fire had happened in Dhruv's kitchen because of oil.

Dhruv's mother told him to use water to put out the fire quickly

Dhruv's father told him to use carbon dioxide fire extinguisher.

What should he use?

• Water

• Carbon dioxide fire extinguisher

• Neither