Match the items of Column A with the items of Column B . Column A Column B (a) Oxides of sulphur and nitrogen (i) fire extinguisher (b) CNG (ii) incomplete combustion of coal (c) Oxygen (iii) very low ignition temperature (d) inflammable substance (iv) acid rain (e) carbon dioxide (v) necessary for combustion (f) carbon monoxide (vi) fuel for automobiles.

(a)Oxides of sulphur and nitrogen -(iv)acid rain Oxides of sulphur and nitrogen react with rain water to form acids which come down to earth as acid rain. (b)CNG - (vi)fuel for automobiles CNG is the natural gas compressed at high pressure which is a clean fuel used for automobiles. (c)Oxygen - (v)necessary for combustion Oxygen is an important condition necessary for combustion. If there is limited or no supply air, then it becomes an incomplete combustion. (d)inflammable substance - (iii)very low ignition temperature Ignition temperature is the minimum temperature for a substance to catch fire. Inflammable substances which catch fire easily have very low ignition temperature. (e) carbon dioxide - (i) fire extinguisher Carbon dioxide cuts the supply of oxygen, hence is used in fire extinguisher. (f) carbon monoxide- (ii) incomplete combustion of coal Carbon monoxide is a harmful gas which is caused due to incomplete combustion of coal. Column A Column B (a) Oxides of sulphur and nitrogen (iv) acid rain (b) CNG (vi) fuel for automobiles. (c) Oxygen (v) necessary for combustion (d) inflammable substance (iii) very low ignition temperature. (e) carbon dioxide (i) fire extinguisher (f) carbon monoxide (ii) incomplete combustion of coal.

Match the following for the flame of a candle. Column A Column B Column C (a) hottest part (i) innermost zone of unburnt wax vapours (x) blue (b) moderately hot (ii) middle zone of partial combustion (y) black (c) least hot (iii) outer zone of complete combustion (z) yellow

(a) the hottest part - (iii) outer zone of complete combustion - (x) blue The hottest part of the flame is the outer zone of complete combustion which is blue. It is the non-luminous zone of a candle flame. (b)moderately hot - (ii) middle zone of partial combustion - (z) yellow The middle zone of the flame is moderately hot which causes partial combustion and is yellow. It is the luminous zone of a candle flame. (c)least hot - (i) innermost zone of unburnt wax vapours - (y)black The innermost part of the flame is the least hot which contains the unburnt wax vapours of the candle. It is black. It is the dark zone of a candle flame. Column A Column B Column C (a) hottest part (iii) outer zone of complete combustion (x) blue (b) moderately hot (ii) middle zone of partial combustion (z) yellow (c) least hot (i) innermost zone of unburnt wax vapours (y)black

E M B I B E

NCERT Exemplar Science - Class 8>Chapter 6 - Combustion and Flame>SHORT ANSWER QUESTIONS>Q 22

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8th CBSE

IMPORTANT

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Air is necessary for combustion.

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Important Questions on Combustion and Flame

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8th CBSE

IMPORTANT

NCERT Exemplar Science - Class 8>Chapter 6 - Combustion and Flame>SHORT ANSWER QUESTIONS>Q 22

Magnesium is a non-combustible metal.

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8th CBSE

IMPORTANT

NCERT Exemplar Science - Class 8>Chapter 6 - Combustion and Flame>SHORT ANSWER QUESTIONS>Q 22

Carbon dioxide is an excellent fire extinguisher.

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8th CBSE

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NCERT Exemplar Science - Class 8>Chapter 6 - Combustion and Flame>SHORT ANSWER QUESTIONS>Q 22

Calorific value of wood is higher than that of coal.

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IMPORTANT

NCERT Exemplar Science - Class 8>Chapter 6 - Combustion and Flame>SHORT ANSWER QUESTIONS>Q 23

Match the items of Column A with the items of Column B.

Column A	Column B
(a) Oxides of sulphur and nitrogen	(i) fire extinguisher
(b) CNG	(ii) incomplete combustion of coal
(c) Oxygen	(iii) very low ignition temperature
(d) inflammable substance	(iv) acid rain
(e) carbon dioxide	(v) necessary for combustion
(f) carbon monoxide	(vi) fuel for automobiles.

HARD

8th CBSE

IMPORTANT

NCERT Exemplar Science - Class 8>Chapter 6 - Combustion and Flame>SHORT ANSWER QUESTIONS>Q 24

Match the following for the flame of a candle.

Column A	Column B	Column C
(a) hottest part	(i) innermost zone of unburnt wax vapours	(x) blue
(b) moderately hot	(ii) middle zone of partial combustion	(y) black
(c) least hot	(iii) outer zone of complete combustion	(z) yellow