When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are?
A
nitrogen and carbondioxide
B
the rare gases
C
nitrogen and oxygen
D
nitrogen and the rare gases
E
nitrogen, carbondioxide and the rare gases
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
- Alkaline solutions of pyrogallol absorb oxygen efficiently.
- Quicklime have a strong chemical affinity to absorb water.
- At room temperature, Calcium oxide (CaO) will spontaneously absorb carbon dioxide from the atmosphere.
Source: Myschool Past Questions Archive (Record #40)