Question

Arrange the following gases in increasing order of their abundances (% units) in atmosphere on dry basis:
A. Carbon dioxide
B. Helium
C. Hydrogen
D. Neon
E. Argon

• A. A, E, C, D, B
• B. B, C, D, E, A
• C. C, D, B, A, E
• D. C, B, D, A, E

Hint:

Always remember the Top 4: Nitrogen > Oxygen > Argon > $CO_2$. Any other noble gases (Neon, Helium) or Hydrogen are much rarer than these four.

Answer 1

The Correct Option is D

Concept: The Earth's atmosphere is a mixture of nitrogen (~78%), oxygen (~21%), and argon (~0.93%), with other gases existing in trace amounts. "Increasing order" means starting from the rarest gas.

Step 1: Identifying Trace Gas Concentrations.

• C. Hydrogen: ~0.00005% (Extremely rare in the lower atmosphere).
• B. Helium: ~0.0005%.
• D. Neon: ~0.0018%.

Step 2: Identifying Major Trace Gases.

• A. Carbon dioxide: Currently ~0.04% (or 400+ ppm).
• E. Argon: ~0.93% (The third most abundant gas in the atmosphere).

Step 3: Sequencing.
The increasing order of abundance is: Hydrogen (C) < Helium (B) < Neon (D) < Carbon dioxide (A) < Argon (E).