Question: In the reaction, \[Fe + 2HCl \to FeC{l_2} + {H_2}\]. What is the oxidation state of \[Fe\] in \[FeC{...

Question

In the reaction, $Fe + 2HCl \to FeC{l_2} + {H_2}$ . What is the oxidation state of $Fe$ in $FeC{l_2}$ ?
A. $+ 2$
B. $+ 3$
C. $+ 4$
D. $+ 5$

Answer 1

Solution

We need to know that the iron is the chemical element having the atomic number $26$ . The iron is a metal which belongs to the first transition series. The belonging group and period are eight and four respectively. The hydrochloric acid is a strong acid having the formula, $HCl$ . The elements present in the compound are hydrogen and chlorine. The ferrous chloride is also known as iron (II) chloride which is a chemical compound with formula, $FeC{l_2}$ .

Complete answer:
The given chemical reaction undergoes both oxidation and reduction reaction. Hence, it is a redox reaction. In this reaction, $Fe + 2HCl \to FeC{l_2} + {H_2}$ , hydrochloric acid acts as the oxidizing agent and iron acts as a reducing agent.
The oxidation – reduction can be written as,
$2{H^I} + 2{e^ - } \to 2{H^0}\left( {Oxidation} \right)$
$F{e^0} - 2{e^ - } \to F{e^{II}}\left( {\operatorname{Re} duction} \right)$
The oxidation state of chloride ions in ferrous chloride is $- 1$ . Let ‘X’ be the oxidation state of iron in $FeC{l_2}$ . Hence, the oxidation state of iron in $FeC{l_2}$ can be found out by substituting the value of oxidation state of chloride ion in $FeC{l_2}$ .
$X + 2\left( { - 1} \right) = 0$
$X - 2 = 0$
$\Rightarrow X = 0$
Therefore, the oxidation state of iron in $FeC{l_2}$ is equal to $+ 2$ . Hence, option (A) is correct.
The oxidation state of ferrous chloride will not equal $+ 3$ . Hence, the option (B) is incorrect.
The oxidation state of $Fe$ in $FeC{l_2}$ is not equal to $+ 4$ . Hence, the option (C) is incorrect.
By substituting the oxidation state of chloride in $FeC{l_2}$ , the oxidation state of iron will not get as $+ 5$ . Hence, the option (D) is incorrect.

So, the correct answer is “Option A”.

Note:
As we know, the oxidation – reduction reaction is also known as redox reaction. This is a type of chemical reaction that undergoes the transfer of electrons between two species. During a chemical reaction, the oxidation state of an atom, molecule or ion may change. It may increase or decrease the oxidation number by losing or gaining the electrons.