Question

Give the chemical tests to distinguish between the following gases:

Oxygen and ammonia

Answer 1

In practical Chemistry, two types of analysis are done.

1. Qualitative analysis: The analysis which aims at detecting the presence of any substance in a given sample.
2. Quantitative analysis: The analysis which aims at knowing the quantity of any substance present in a sample.

These chemical tests include the chemical reactions of the gases with other chemicals that help us to confirm the gas by qualitative analysis.

• Physical tests like colour and odour are also helpful but do not help to confirm the gas.
• Chemical tests to distinguish between Oxygen and Ammonia are as follows:

Name of the test	Oxygen $\left({\mathrm{O}}_2\right)$	Ammonia $\left({\mathrm{NH}}_3\right)$
Rekindling of glowing splinter	Oxygen gas rekindles a glowing splinter. This is because Oxygen supports combustion reaction. Combustion: It is a process where a substance reacts with oxygen to release energy in the form of heat or light.	Ammonia cannot rekindle a glowing splinter.
Reaction with Hydrochloric acid $\left(\mathrm{HCl}\right)$	Oxygen does not reacts with Hydrochloric acid to produce dense white fumes.	When a rod dipped in Hydrochloric acid $\left(\mathrm{HCl}\right)$ is brought near ammonia, dense white fumes or smog of Ammonium chloride $\left({\mathrm{NH}}_4\mathrm{Cl}\right)$ are produced. $$\begin{gathered} {\mathrm{NH}}_3\left(\mathrm{aq}\right)+\mathrm{HCl}\left(\mathrm{g}\right)\to {\mathrm{NH}}_4\mathrm{Cl}\left(\mathrm{s}\right) \\ \left(\mathrm{Ammonia}\right)(\mathrm{Hydrochloric}\mathrm{acid})(\mathrm{Ammonium}\mathrm{chloride}) \\ (\mathrm{white}\mathrm{fumes}) \end{gathered}$$