Helium gas is filled in balloons because
A. Its atomic number is 2
B. It is lighter than air
C. It is one of the constitutents of water
D. It is a noble gas
Answer: Option B
Solution(By Examveda Team)
Because of the Archimedes’ principle, a lifting gas is required for aerostats to create buoyancy. Its density is lower than that of air (about 1.29 kg/m3, 1.29 g/ L). Only certain lighter than air gases are suitable as lifting gases. Hydrogen and helium are the most commonly used lift gases. Although helium is twice as heavy as (diatomic) hydrogen, they are both so much lighter than air that this difference is inconsequential. Both provide about 9.8 N of lift (1 Newton is the force required to accelerate 1 kg at 1 m/sec2) per cubic meter of gas at STP. Helium is the second lightest gas. For that reason, it is an attractive gas for lifting as well. A major advantage is that this gas is noncombustible. Today helium is used instead of hydrogen, since it is inert so non-flammable which makes things a lot safer. Hydrogen can ignite very easily when mixed with the oxygen of the surrounding air.Related Questions on Chemistry
Which of the following phenomenon is considered responsible for Global Warming?
A. Greenhouse effect
B. Fire in coal mines
C. Dry farming
D. Monsoon
E. Trade winds
The nucleus of an atom consists of
A. electrons and neutrons
B. electrons and protons
C. protons and neutrons
D. All of the above
The number of moles of solute present in 1 kg of a solvent is called its
A. molality
B. molarity
C. normality
D. formality
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