Answer: The process by which a particular substance or different substances are transformed to another is called as Chemical Reaction.One reason, in the case of reversible reactions could be that the reaction reached equilibrium before the reaction was complete.Chemical reactions occur when chemical bonds between atoms are formed or broken. The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products.The concentration of reactants decreases as the reaction proceeds and at last their concentration comes to an end. Hence, the reaction stops too. If two reactants are being reacted, then the reactant which is in limited amount will consume first and will result in the termination of reaction.The usual reason is that one (or more) of the reactants gets used up.
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