Question

The missing term in the following equation is
\[2F{{e}^{3+}}+S{{n}^{2+}}\to 2F{{e}^{2+}}+.....\]?
a.) \[S{{n}^{4+}}\]
b.) \[S{{n}^{3+}}\]
c.) \[S{{n}^{2+}}\]
d.) \[S{{n}^{+}}\]

Answer 1

Hint: In a chemical reaction always one chemical undergoes oxidation (loss of electrons) and one chemical undergoes reduction (gain of electrons). If both oxidation and reduction happens in the same reaction then the chemical reaction is called redox reaction.

Complete step by step answer:
We have to find the missed chemical term in the given chemical reaction.
The given chemical reaction is

 \[2F{{e}^{3+}}+S{{n}^{2+}}\to 2F{{e}^{2+}}+.....\]
In the above chemical reaction the exchange of electrons is happening in between iron (Fe) and tin (Sn).
The oxidation number of iron in the reactant side is +3 and the oxidation number of iron in the product side is +2.
Means the oxidation number of iron is decreased in the product side means reduction is occurred in case of iron.
If iron undergoes reduction means the tin metal undergoes oxidation so the oxidation number of tin is supposed to be increased.
 Two moles of iron accept two electrons from the reactant side, so those two electrons should come from tin.
Therefore the oxidation number of tin is going to change from +2 to +4. The chemical reaction of tin will be as follows.
 \[S{{n}^{2+}}\to S{{n}^{4+}}+2{{e}^{-}}\]
Therefore the missed chemical component in the above is \[S{{n}^{4+}}\].

The overall reaction will be
\[2F{{e}^{3+}}+S{{n}^{2+}}\to 2F{{e}^{2+}}+S{{n}^{4+}}\]
So, the correct answer is “Option A”.

Note: To find the missing chemical component in a chemical reaction we have to find the number of electrons exchanged between the chemicals and which element is undergoing oxidation and which element is undergoing reduction reaction. Then only we can find the missed chemical component easily.