Concept:Redox reactions are chemical processes in which oxidation and reduction happen at the same time.
Explanation:Oxidation is the loss of electrons or an increase in oxidation state.
Reduction is the gain of electrons or a decrease in oxidation state.
Electrons that are lost during oxidation must be gained by another substance.
Therefore, oxidation cannot occur alone without reduction.
In the same reaction, one species is oxidised while another species is reduced simultaneously.
For example, when zinc atoms react with copper ions, zinc loses electrons while copper ions gain electrons.
The oxidation number of zinc increases from
0 to
+2, while that of copper decreases from
+2 to
0.
Since reduction and oxidation occur together in a single process, such reactions are called redox reactions.
The term "redox" is formed from the words reduction and oxidation.
Thus, the reactions involving simultaneous oxidation and reduction are correctly described as redox reactions.
Answer:D. Redox reactions