Question

Assertion :The rate of reaction decreases with a decrease of concentration and increase with an increase of the concentration of reactants. Reason: The rate of reaction is directly proportional to the concentration of reactants.

• A. If both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. If both Assertion and Reason are correct, but Reason is not the correct explanation for Assertion.
• C. If Assertion is correct, but Reason is incorrect.
• D. If Assertion is incorrect, but Reason is correct.

Answer 1

The correct option is A If both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

The rate of a given chemical reaction is the measure of the change in concentration of the reactants or the change in concentration of the products per unit time.

For the reaction:

$A+B\to C+DRate=\frac{-d\left[A\right]}{dt}=\frac{-d\left[B\right]}{dt}=\frac{d\left[C\right]}{dt}=\frac{d\left[D\right]}{dt}Rate=k\left[A\right]\left[B\right]$

Therefore rate decreases with decrease in the concentration of reactants and increases with an increase in product concentration.

As it is directly proportional to the change in concentrations of reactants and products

Option A is correct as assertionand reason are correct and related.