Question

Which of the following is correct for Reduction reaction?
A. Addition of electrons
B. Decrease in oxidation state of element
C. Addition of hydrogen
D. All of these

Answer 1

Hint:we can take an example here that when iron is reacted with oxygen it resulted in the formation of iron oxides thus we can say that iron is oxidised to iron oxide and oxygen is reduced. Reduction reactions occur in the presence of a reducing agent.

Complete answer:
As we know that reduction reaction is a type of chemical reaction occurring between two chemicals or atoms which involves the gaining of electrons by one of the atoms, or the element that accepts the electrons from another element as the oxidation state of the element that gains electron is lowered.
We can give a simple example here;
When iron reacts with oxygen it results in the formation of iron oxides thus we can say that iron is oxidised to iron oxide and oxygen is reduced. It is called a redox reaction where both oxidation and reduction is taking place simultaneously.
Reduction reaction also involves the addition of hydrogen atoms which are lost by the oxidation in the same reaction and reduction is also accompanied by the loss of oxygen atoms. When a molecule is reduced, it generally gains energy.
So in total we can say that a reduction reaction is the gain or addition of electrons, loss of oxygen, gain or addition of hydrogen and the decrease in the oxidation state of the element.

Therefore the correct answer is (D). All of these

Note:
Remember that when an oxidation number of an atom is decreased in the course of a redox reaction involving both phenomenon of oxidation as well as reduction, that atom is being reduced. The reducing agent undergoes oxidation and the oxidising agent undergoes reduction in a chemical redox reaction.