Answer :
(a) Reactant Mg is oxidized and reactant Fe is reduced.
(b) Reactant C is oxidized and reactant Cu is reduced.
Explanation :
As we know that a reactant is either reduced or oxidized in a chemical reaction.
- If the oxidation state of an atom is decreases or gains electrons from reactant to product side then we can say that the reactant is reduced that means reduction.
- If the oxidation state of an atom is increases or loses electrons from reactant to product side then we can say that the reactant is oxidized that means oxidation.
Part (a):
The given word equation of chemical reaction is:
Magnesium metal + Aqueous iron (III) sulphate → Iron metal + Aqueous magnesium sulphate
The balanced chemical equation of this word equation will be:
[tex]3Mg(s)+Fe_2(SO_4)_3(aq)\rightarrow 2Fe(s)+3MgSO_4(aq)[/tex]
In this reaction, the oxidation state of reactant Mg changes from (0) to (+2) that shows oxidation due to increase in oxidation state. So, we can say that Mg is oxidized.
And, the oxidation state of reactant Fe changes from (+3) to (0) that shows reduction due to decrease in oxidation state. So, we can say that Fe is reduced.
Part (b):
The given word equation of chemical reaction is:
Solid carbon + Solid copper oxide → Carbon dioxide gas + Copper metal
The balanced chemical equation of this word equation will be:
[tex]C(s)+2CuO(s)\rightarrow CO_2(g)+2Cu(s)[/tex]
In this reaction, the oxidation state of reactant C (carbon) changes from (0) to (+4) that shows oxidation due to increase in oxidation state. So, we can say that C is oxidized.
And, the oxidation state of reactant Cu changes from (+2) to (0) that shows reduction due to decrease in oxidation state. So, we can say that Cu is reduced.