JAMB - Chemistry (1978 - No. 9)
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?
nitrogen and carbondioxide
the rare gases
nitrogen and oxygen
nitrogen and the rare gases
nitrogen, carbondioxide and the rare gases
Vysvetlenie
- 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.