Question

A reversible reaction is one which:
A: Proceeds in one direction.
B: Proceeds in both directions.
C: Proceeds spontaneously.
D: All the statements are wrong.

Answer 1

Hint: A chemical reaction refers to a phenomenon which leads to the chemical transition of one type of chemical substance to another. The substances (one or more than one) initially participating in a chemical reaction are known as reactants. These chemical reactions undergo a chemical change, resulting in the formation of either one or more products that usually possess properties distinct from the reactants.

Complete answer:
There are two types of reactions i.e. reversible and irreversible chemical reactions.
> If the reaction takes place only in one direction, then it is Irreversible chemical reaction. This means that the reactants can form products, but the formed products cannot convert back to the reactants.
> If chemical reactions occur in both directions, then these reactions are called reversible reactions. Not only can the reactants change to the products, but the products can change back to the reactants, at least under certain conditions.
Consider the reaction in which hydrogen gas and oxygen gas combine to produce water. This reaction is reversible if an electric current is applied to the water that is produced. The current causes the water molecules to break down to individual hydrogen and oxygen atoms. Then these atoms recombine to form molecules of hydrogen gas and oxygen gas.
This reversible chemical equation would be:
1. A reversible reaction is one which proceeds in both directions (forward and backward).
For example, consider the reaction . It is a reversible reaction. The forward direction is
$A\xrightarrow{{}}B$. The reverse direction is $B\xrightarrow{{}}A$.
2. In a reversible reaction, the reactants and products of the reaction may reverse roles. Just look at the following reversible reaction:
In this reaction,
\[{H_2}\left( g \right) + {\text{ }}{I_2}\left( g \right)\xrightarrow{{}}2HI{\text{ }}\left( g \right)\]is a forward reaction i.e. (left to right)

\[2HI{\text{ }}\left( g \right)\xrightarrow{{}}{H_2}\left( g \right) + {\text{ }}{I_2}\left( g \right)\] is a reverse reaction i.e. (right to left).

Thus, the correct answer to the given question is (B) i.e. A reversible reaction is one which proceeds in both directions.

Note: Remember that $\xrightarrow{{}}$ implies that A goes to B and cannot become A again. On the other hand, implies that the reaction is reversible which means that A can go to B and B can go to A.