Oxygen content below __________ percent in air contaminated with nitrogen does not support combustion and is unsafe for humane exposure.

— air is composed of about 78 percent nitrogen and |. only about 21 percent oxygen, is a little known fact -_. on the streets.

A

How that

B

This

C

When

D

However

The arrangement made to support an unsafe structure temporarily, is known as

A

Shoring

B

Scaffolding

C

Underpinning

D

Jacking

Exposure to mixtures of chemicals are greater than expected on the basis of effects of exposure to each chemical individually. This is known as

A

Additives

B

Antagonism

C

Synergism

D

Independent

Presence of nitrogen in combustion air does not reduce the

A

Amount of heat liberated

B

Flame temperature

C

Flue gas temperature

D

Any of the above

Ionisation energy of nitrogen is greater than that of oxygen because nitrogen has

A

High bond dissociation energy

B

Smaller atomic radius

C

Stable half filled 2p sub level

D

High nuclear charge

Oxygen enrichment of combustion air does not result in increase of the

A

Flame temperature

B

Oxygen in the flue gas

C

Stack loss

D

Heat transfer rate in the furnace

Nitrogen content in ammonium sulphate (a fertiliser) is around __________ percent.

A

5

B

20

C

50

D

65

Nitrogen content of urea is about __________ percent.

A

10

B

46

C

80

D

94

Nitrogen content of calcium ammonium nitrate (CAN) is __________ percent.

A

10

B

25

C

50

D

80

Use of excess of combustion air in the combustion of fuels results in

A

Heat losses

B

Long flame

C

Condensation of water vapour from the fuel gas

D

None of these

Oxygen content below __________ percent in air contaminated with nitrogen does not support combustion and is unsafe for humane exposure.

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