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

The correct answer is D. nitrogen and the rare gases

- 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.

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