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Question-1
________ fuels do not leave any residue after burning.

(A) Solid	(B) Gaseous
(C) Liquid	(D) Primary

Question-2
Combustion is a _____ reaction accompanied by heat and light.

(A) reduction	(B) redox
(C) substitution	(D) oxidation

Question-3
Types of combustion are:

(A) rapid	(B) spontaneous, rapid and explosive:
(C) explosive	(D) spontaneous

Question-4
Which among the following is the best fuel?

(A) Wood 4000 Cal/g	(B) Coke 8000 Ca/g
(C) Coal 7000 Cal/g	(D) Kerosene 11,200 Cal/g

Question-5
Mark the corret statement.

(A) Different substances catch fire at the same temperature.	(B) Different substances catch fire at different temperatures
(C) Same substances can catch fire at different temperatures.	(D) None of these

Question-6
Which one of these is/are essentials of a fire?

(A) Heat	(B) Fuel
(C) Oxygen	(D) All of these

Question-7
Which of the following has the characteristics of a good fuel?

(A) Coke	(B) Butane
(C) Coal	(D) Kerosene

Question-8
When ignition temperature of a substance is _____ it will readily catch fire.

(A) Low	(B) High
(C) Constant	(D) Medium

Question-9
During an exothermic process _________ is released

(A) Light	(B) Heat
(C) Oxygen	(D) Air

Question-10
When a hydrocarbon fuel is burnt in a sufficient supply of air__________ and _________are produced.

(A) CO, CO₂	(B) CO₂, H₂O vapours
(C) CO, H₂O vapours	(D) H₂O liquid, H₂O vapours

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Std 8

CBSE

Practice in Related Chapters
Combustion,flame and fuel
Coal and Petroleum
Synthetic Fibres and Plastics
Pollution of Air and Water
Metals and Non-Metals