Question

I. Fill in the blanks :-

a. One should never use water for extinguishing ______ fires.

b. Combustion of food inside living cells occurs through ______ .

c. Nowadays in place of petrol and diesel, a cleaner fuel ______ is

recommended.

d. If ignition temperature of a substance is lower than room temperature

then it will undergo ______ combustion.

e. Wax vapours burn completely in ______ zone of a candle flame.

II. State whether the following statements are true or false:

a. If ignition temperature is higher than room temperature, the fuel is

considered good.

b. Combustion is an oxidation process.

c. If supply of oxygen is insufficient during combustion, carbon dioxide is

formed instead of carbon monoxide.

d. Any combustion reaction not accompanied by flame is known as

burning.

II. Match the column :-

Column A Column B

a. Carbon dioxide i) also called gobar gas

b. Oxygen ii) highest calorific value

c. Hydrogen iii) gas essential for burning

d. Biogas iv) non pollutant vehicular fuel

e. CNG v) used in fire extinguisher

III. Answer the following:

1. Name a few fuels used in our homes.

2. Name a few fuels used in trade and industry.

3. What fuels are used for running automobiles?

4. What is the difference between the burning of a candle and burning of

a fuel like coal?

5. What is combustion?

6. Define a fuel?

7. (i) What are the essential condition required for combustion?

(ii) What is the essential condition required for extinguishing fire?

8. What are inflammable substance? Give examples.

9. In what form is LPG stored in cylinders?

10.Name the most common fire extinguisher?

11.Water is not suitable for extinguishing fires involving electrical

equipment oil and petrol. Why?

12.Explain how CO2 is able to control fires?

Answer 1

I)
a.Electrical
b.Respiration/cell respiration
c.CNG(compressed natural gas)
d.Spontaneous
e.middle

II)
A. TRUE: if the ignition temperature is lower than,the room temperature,it will be spontaneous and can cause fire accidents.

B. TRUE:during combustion the fuel react with oxygen,to ignite hence is an oxidation process

C. FALSE: when oxygen is insufficient carbon monoxide is formed(CO) when there is excess of oxygen carbon dioxide(CO2) if formed.

D. FALSE: combustion with flame is called burning.

II) match the following:

A---＞ (v)
B---＞(iii)
C---＞(ii)
D---＞(i)
E---＞(iv)