Chemistry - Study Mode

[#876] White coal is
Correct Answer

(D) None of these

Explanation

Solution: White coal is a form of fuel produced by drying chopped wood over a fire.

[#877] Which of the following is the petroleum wax ?
Correct Answer

(C) Paraffin wax

Explanation

Solution: Paraffin wax is obtained from petroleum by dewaxing light lubricating oil stocks. It is used in candles, wax paper, polishes, cosmetics, and electrical insulators.

[#878] Water is not effective in extinguishing a fire caused by petrol because
Correct Answer

(D) Water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn

Explanation

Solution: As water is heavier than petrol therefore slips down permitting the petrol to rise to the surface and continue to burn. Besides, the existing temperature is so high that the water poured on the fire evaporates even before it can extinguisher the fire. Thus the petrol fire cannot be extinguished by water.

[#879] Helium gas is used in gas balloons instead of hydrogen gas because it is
Correct Answer

(C) Non-combustible

Explanation

Solution: Helium gas is lighter than air, therefore, a helium balloon rises, it is known as a noble gas and is therefore not reactive. Hydrogen is also lighter than air and even lighter than helium. However, Hydrogen is not used in balloons because it is highly explosive and flammable.

[#880] Global warming may result in
Correct Answer

(D) All of the above

Explanation

Solution: Global warming may result in flood, cyclone and decrease in forest productivity.