Which of the following statement is correct?

Options

A. The rate of a reaction decreases with passage of time as the concentration of reactants decreases.
B. The rate of a reaction is same at any time during the reaction
C. The rate of a reaction is independent of temperature change
D. The rate of a reaction decreases with increase in concentration of reactant(s)

Explanation

To determine which statement about the rate of reaction is correct, we will analyze each statement one by one based on the principles of chemical kinetics.

1. **Statement 1: Rate of reaction decreases with the passage of time as the concentration of the reactant decreases.**
- This statement is true. As a reaction progresses, the concentration of the reactants decreases, leading to fewer molecules available for collisions. Since the rate of reaction is dependent on the frequency of collisions between reactant molecules, a decrease in concentration results in a decrease in the rate of reaction.

2. **Statement 2: Rate of the reaction is the same at any time during the reaction.**
- This statement is false. The rate of reaction is not constant; it changes over time as the concentrations of reactants change. Initially, when reactants are abundant, the rate is higher, but as the reaction proceeds and reactants are consumed, the rate decreases.

3. **Statement 3: Rate of reaction is independent of temperature change.**
- This statement is also false. The rate of reaction is significantly affected by temperature. Generally, an increase in temperature increases the kinetic energy of molecules, leading to more frequent and energetic collisions, which typically increases the rate of reaction.

4. **Statement 4: Rate of reaction decreases with an increase in concentration of reactant.**
- This statement is incorrect. In most cases, increasing the concentration of reactants leads to an increased rate of reaction because there are more molecules available for collisions.

Based on the analysis above, the only correct statement is:

**Correct Statement: Rate of reaction decreases with the passage of time as the concentration of the reactant decreases.**