Question

What are the reactants and products in a chemical reaction?

Answer 1

Answer : The species present on the left side of the right arrow in the reaction are known as reactant and the species present on the right side of the right arrow in the reaction are known as product.

Explanation :

Balanced chemical reaction : It is defined as the reaction in which the number of atoms of an individual elements present on reactant side must be equal to the product side.

The reactant and product species present in the reaction are separated by right arrow.

The species present on the left side of the right arrow in the reaction are known as reactant and the species present on the right side of the right arrow in the reaction are known as product.

For example :

$2H_2(g)+O_2(g)\rightarrow 2H_2O(l)$

This reaction is a balanced chemical reaction because in this reaction the number of atoms of an individual elements are equal on both side of the reaction.

In this reaction, $H_2$ and $O_2$ are the reactants and $H_2O$ is the product.

Answer 2

The reactant is the chemical reaction of 2 or more different elements. 
The product is what is formed in a chemical reaction. 

Example: H + O ---->  H2O 
H + O is the reactants, and H2O is the products.