Question

Which would quickly absorb oxygen?
A. Alkaline solution of pyrogallol
B.Conc.${H_2}{S{O_4}}$
C.Lime water
D.Alkaline solution of ${Cu}{S{O_4}}$

Answer 1

Hint: We know that different compounds can absorb different gases but their rate of absorption differs. In order to answer this question, we need to know about Orsat gas analyzer which is an equipment used to know the contents of various gases. In this equipment, we use different adsorbents like Copper chloride, Potassium hydroxide and Pyrogallol. Let us get into the details.

Complete answer:
I have mentioned the names of a few absorbents; we shall try to know what gases they absorb. In this equipment, Copper chloride is used as absorbent for Carbon monoxide, Potassium hydroxide is used for carbon dioxide and pyrogallol is used for oxygen. Now it is clear that pyrogallol absorbs oxygen. The next option is concentrated sulphuric acid; it can absorb oxygen but not as fast as pyrogallol. The rate of oxygen absorbed by it is low when compared to pyrogallol. The next option is lime water which absorbs carbon dioxide quickly but not the oxygen, so you can rule this out. Alkaline solution of copper sulphate cannot absorb oxygen. The alkaline solution of pyrogallol is colorless and upon absorbing oxygen, it turns into a brown color. By the above explanation, it is clear that pyrogallol can absorb oxygen at a faster rate than any other compound.

So, the correct option is A.

Note:
This pyrogallol is said to be used in determining the amount of oxygen present in a mixture of gases. It can be naturally obtained from an aquatic plant named Myriophyllum spicatum. When oxygen gas is passed through pyrogallol, the solution turns brown.