The rate equation for a chemical reaction is rate of reaction = [Χ] [Υ] Consider the following statements in this regard:

(A) The order of reaction is one

(B) The molecularity of reaction is two

(C) The rate constant depends upon the temperature

Of these statements

B and C are correct

The correct answer is option 3. B and C are correct.

Let us delve into each statement and its relationship to the given rate equation:

Rate Equation: \( \text{rate of reaction} = [\text{X}] [\text{Y}] \)

This rate equation suggests that the rate of the reaction is directly proportional to the concentrations of both reactants X and Y.

Analysis of each statement:

(A) The order of reaction is one

The order of a reaction is determined by summing the exponents of the concentration terms in the rate law. Here, the rate law is \( \text{rate} = [\text{X}] [\text{Y}] \).

The concentration term for both X and Y in the rate law has an exponent of 1. Therefore, the overall order of the reaction is \( 1 + 1 = 2 \), not 1.

Thus, Statement A is incorrect because it incorrectly identifies the order of the reaction as one, whereas it is actually two.

(B) The molecularity of reaction is two

Molecularity refers to the number of molecules or ions participating in the rate-determining step of a reaction. In the rate equation \( \text{rate} = [\text{X}] [\text{Y}] \), both X and Y are directly involved in determining the rate of the reaction. This suggests that the reaction is bimolecular, meaning it involves the collision of two molecules (one X and one Y) in the rate-determining step. Therefore, Statement B is correct because it accurately identifies the molecularity of the reaction as two.

(C) The rate constant depends upon the temperature

According to the Arrhenius equation, the rate constant \( k \) is dependent on temperature. The Arrhenius equation is given by \( k = A e^{-\frac{E_a}{RT}} \), where \( A \) is the pre-exponential factor, \( E_a \) is the activation energy, \( R \) is the gas constant, and \( T \) is the temperature in Kelvin. An increase in temperature generally increases the rate constant \( k \) because higher temperatures provide more kinetic energy to the reacting molecules, leading to more frequent and energetic collisions.

Therefore, Statement C is correct because the rate constant \( k \) does indeed depend on temperature due to its influence on the rate of collisions and the energy barrier (activation energy) for the reaction.

Conclusion:

Statement B (The molecularity of reaction is two) correctly identifies the nature of the reaction involving two molecules in the rate-determining step.

Statement C (The rate constant depends upon the temperature) correctly reflects the fundamental principle that the rate constant \( k \) is influenced by temperature changes.

Statement A (The order of reaction is one) is incorrect because it misidentifies the order of the reaction based on the rate equation provided.

Therefore, the correct answer is: 3. B and C are correct.