Question

For any chemical reaction, at the start of reaction concentration of the 1 is maximum and the concentration of products is 2 . As the reaction proceeds, the concentration of reactants 3 gradually and the concentration of the product 4 gradually. The change in concentration of the reactant or product with respect to time is known as
the 5 .

Answer 1

$1\to$reactant

$2\to$zero

$3\to$decreases

$4\to$increases

$5\to$rate of reaction

Initially, in a reactor only reactants are present & products are yet to be produced. But as the time passes, the reactants react to give product which results in the decreases inconcentration of reactants & increase in concentration of products. This change of concentration of either of reactant or product with respect to time is known as the rate of the reaction.