NEETChemistryChemical Kinetics
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): For a chemical reaction, the plot of k versus 1 T is a straight line with a negative slope. Reason (R): The activation energy of a reaction decreases with an increase in temperature, leading to a higher rate constant. In the light of the above statements, choose the most appropriate answer from the
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is not correct but (R) is correct
- D(A) is correct but (R) is not correct
Correct answer
D. (A) is correct but (R) is not correct
Step-by-step solution
Assertion (A) is correct. According to the Arrhenius equation, k = A e^ -E_a/RT . Taking the natural logarithm on both sides gives k = A - E_a RT . This represents a straight line equation ( y = mx + c ) where the slope is - E_a R , which is a negative value. Reason (R) is not correct. The activation energy ( E_a ) of a reaction is characteristic of the reaction and is generally independent of temperature. The rate constant increases with temperature because a larger fraction of molecules acquires kinetic energy gr