Question

_________ chemical which absorbs oxygen in air.

Answer 1

Hint: Air is a mixture of various types of gases, but mainly nitrogen, oxygen and carbon dioxide.

Complete Answer:
The chemical which can absorb oxygen in air is pyrogallol. The characteristics of pyrogallol are as follows,
- It is an organic compound
- It is solid in nature
- It is white in colour
- It is sensitive towards presence of oxygen

In nature, pyrogallol (${C_6H_3({OH})_3}$) is present naturally in an aquatic plant known as Myriophyllum spicatum. This plant produces pyrogallic and when this acid is present in an alkaline solution it absorbs oxygen from the air. The indicator for the reaction is that it turns brown from a colourless solution. It can be one of the ways to calculate the amount of oxygen present in air.

Note: Nitrogen from air can be removed by soda lime. Carbon dioxide from air can be absorbed by plants, sodium hydroxide, lithium hydroxide, etc.