Question

The gases absorbed by alkaline pyrogallol and carbon tetrachloride are_________
respectively
A.) ${{O}_{3}},C{{H}_{4}}$
B.) ${{O}_{2}},{{O}_{3}}$
C.) $S{{O}_{2}},C{{H}_{4}}$
D.) ${{N}_{2}}{{O}_{4}},{{O}_{3}}$

Answer 1

Hint: The concept to be used is of absorption of gases by different materials. Pyrogallol is an organic compound used to check and quantify the amount of oxygen in mixtures.
- Similarly carbon tetrachloride is used to absorb gases like ozone.

Complete Solution :
Absorption is a physical or chemical phenomenon or a process in which atoms, molecules or ions enter some bulk phase – liquid or solid material. This is a different process from adsorption, since molecules undergoing absorption are taken up by the volume, not by the surface .
- Pyrogallol is a phenol compound having weak acidic properties initially obtained from heating Gallic acid is used to absorb oxygen gas from mixtures. Also in laboratories,it is found in a brownish state due to absorption of oxygen gas from the atmosphere.
- Also carbon tetrachloride is a colourless liquid non polar compound used in chemical analysis where ozone gas needs to be absorbed from the mixture.
So pyrogallol absorbs oxygen ${{O}_{2}}$ and carbon tetra chloride absorbs ${{O}_{3}}$.
So, the correct answer is “Option B”.

Note: Carbon tetrachloride is a covalent bonded molecule which finds a variety of practical applications.
- It is being used as a non polar solvent in organic chemistry.
- Large quantities of carbon tetrachloride were used to produce the chlorofluorocarbon refrigerants but were later discontinued as they played a major role in ozone depletion.
- Pyrogallol is also used in isolation of inert gases from a mixture of gases, which requires absorption of oxygen from the mixture.
- There are two types of absorption processes which are chemical and physical absorption.