Question

In the reaction, \[{H_2}S + C{l_2} \to 2HCl + S\], the oxidizing agent is:
(A) ${H_2}S$
(B) $C{l_2}$
(C) ${H_2}$
(D) $HCl$

Answer 1

Hint:The reaction of Hydrogen sulphide with chlorine gas is an example of a redox reaction. In redox reactions, the oxidation state of atoms or molecules gets changed. Oxidation state can be defined as the total number of electrons gained or lost by an atom while forming a bond with another atom.

Complete step by step answer:
A redox reaction is given as a chemical reaction which is governed via transfer of electrons between two atoms or molecules participating in the reaction. This transfer of electrons is observed by calculating the changes that occur in the oxidation states of the reacting species.
In Redox reactions both oxidation and reduction take place in the same reaction. In this type of chemical reaction, one species is oxidised and the other is reduced.
The molecule in which the addition of electrons takes place gets reduced, and the other from which the removal of electrons takes place gets oxidized.
Now, let’s analyse the given reaction:
\[{H_2}S + C{l_2} \to 2HCl + S\]
In the reaction, the oxidation state of $H$ in ${H_2}S$ zero, and it becomes $ + 1$ in $HCl$, on the other hand, the oxidation state of $Cl$ decreases from $0$ to $ - 1$ in $HCl$. Hence, we can say that ${H_2}$ is oxidized and $Cl$ is reduced in the given reaction. As we know, the species that gets oxidized is called the reducing agent, and the species that is reduced is called the oxidizing agent. Hence, we can say that the oxidizing agent in the reaction is ${H_2}S$.
Therefore, option (A) is correct.

Note:
Oxidation numbers represent the potential charge present on an atom in its ionic form. If the atom's oxidation is decreased in a reaction, then it is said to get reduced. If it increases, then the atom is said to get oxidized.