Question

The gas which has a rotten egg smell is:
A. hydrogen peroxide
B. chlorine
C. hydrogen sulphide
D. carbon dioxide

Answer 1

Hint: Identify the smell of each gas by taking into account everyday experiences. Think about what the compounds in the given options may smell like based on their constituents.

Complete step by step answer:
We will look at the properties of each of the given options one by one to determine the correct answer.
- Hydrogen peroxide
The chemical formula of hydrogen peroxide is given as ${{H}_{2}}{{O}_{2}}$. When in pure form, it has a very light blue colour and is colourless when dissolved in water. It has a very sharp smell and is used as an oxidizer, a bleaching agent, and also as antiseptic. The uses will give you an idea about how hydrogen peroxide smells. Thus, this is not the correct answer.

- Chlorine
Chlorine is an element with the chemical symbol $Cl$ and the atomic number 17. It is one of the halogens that are present in the seventeenth group of the periodic table. Chlorine is a yellow-green gas at room temperature and has a pungent and strong odour like bleach. It is used as an antibacterial agent that is used to disinfect water for drinking purposes as well as in swimming pools. So, this is not the correct answer.

- Hydrogen sulphide
Hydrogen sulphide has a chemical formula of ${{H}_{2}}S$. It is a colourless, chalcogen (compounds that contain elements from group 16) hydride gas and is extremely poisonous. It comes with an odour that is like rotten eggs. Its main uses are to produce sulphuric acid and sulphur. Thus, this is the correct answer.

- Carbon dioxide
It has the chemical formula of $C{{O}_{2}}$. It is a colourless, transparent, and odourless gas that can cause suffocation if present in excess quantity in air. It is a major component of the carbon cycle. Thus, this is not the correct answer.
So, the correct answer is “Option C”.

Note: Almost all compounds that contain sulphur have a strong and unpleasant odour. They are usually associated with a pungent or acidic smell, but hydrogen sulphide is the only one that has a characteristic rotten egg smell.