Consider the following constituent gases of the atmosphere :
- 1. Argon
- 2. Neon
- 3. Helium
- 4. Carbon dioxide
Which one of the following is the correct ascending sequence of the above gases in terms of the volume percentage?
1-3-2-4
1-4-2-3
4-2-3-1
2-4-1-3
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC CDS-1 – 2018
1. Argon (Ar): ~0.93%
2. Neon (Ne): ~0.0018%
3. Helium (He): ~0.0005%
4. Carbon dioxide (CO₂): ~0.04% (This value can slightly vary depending on the source/year, but its relative position is stable).
The correct ascending order by volume percentage is Helium (3) < Neon (2) < Carbon dioxide (4) < Argon (1). This corresponds to the sequence 3-2-4-1. Looking at the options provided: A) 1-3-2-4 (Ar, He, Ne, CO2) - Incorrect B) 1-4-2-3 (Ar, CO2, Ne, He) - This sequence (0.93%, 0.04%, 0.0018%, 0.0005%) represents the correct *descending* order of the gases. C) 4-2-3-1 (CO2, Ne, He, Ar) - Incorrect D) 2-4-1-3 (Ne, CO2, Ar, He) - Incorrect Based on standard scientific values, none of the options represent the correct ascending sequence (3-2-4-1). However, option B presents the correct descending sequence (1-4-2-3). It is highly probable that there is an error in the question asking for "ascending" instead of "descending", or a misprint in the options. Given that a forced choice from the options is required and B is the correct descending order, it is often the case in such flawed questions that the option matching the reverse order is the intended answer due to a mistake in the question phrasing. Assuming this likely error, we select B.
– Carbon dioxide, Neon, and Helium are trace gases, present in much smaller quantities.
– The order of abundance for the given gases is Argon > Carbon dioxide > Neon > Helium.