Question

What do you observe when ${{H}_{2}}S$ gas passed through cadmium chloride solution? Name the type of reaction:
A. Synthesis
B. Displacement
C. Double displacement
D. Neutralization

Answer 1

Hint: Hydrogen sulphide is gas having a smell like rotten egg. Generally the sulphide which is present in hydrogen sulphide gas is highly reactive. Hydrogen sulphide reacts with others and sulphide forms derivatives very easily.

Complete step by step solution:
- In the question it is asked what we will observe ${{H}_{2}}S$ gas passed through the cadmium chloride solution.
 - We have to find which type of reaction it is.
- The chemical reaction of hydrogen sulphide with cadmium chloride is as follows.
\[{{H}_{2}}S+CdC{{l}_{2}}\to CdS+2HCl\]

- In the above reaction one mole of hydrogen sulphide reacts with one mole of cadmium chloride and forms one mole of cadmium sulphide and two moles of hydrochloric acid as the products..
- In the above chemical reaction we can see clearly that the two chlorine atoms present in cadmium chloride are replaced with one sulphur atom.
- The displacement of two chlorines in cadmium chloride with one single sulphur atom is a best example for double displacement reaction.
- Therefore the reaction of hydrogen sulphide with cadmium chloride is a double displacement reaction.
So, the correct answer is “Option C”.

Note: Adding chemicals to a particular substance is called an addition reaction. Adding chemicals by displacing other chemicals present in a particular chemical is called displacement reaction. If two chemicals are going to displace in a chemical reaction then it is called double displacement reaction.