NEETChemistryChemical Kinetics
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The plot of k versus 1 T yields a straight line with a positive slope for all chemical reactions. Reason (R): The activation energy ( E _ a ) for any chemical reaction is always a positive quantity. In the light of the above statements, choose the most appropriate answer from the options given belo
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 correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
D. (A) is not correct but (R) is correct
Step-by-step solution
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 is an equation of a straight line ( y = mx + c ) where y = k and x = 1 T . The slope of this line is m = - E _ a R . Since the activation energy ( E _ a ) is the minimum extra amount of energy required by a reacting molecule to get converted into product, it is inherently a positive quantity. The universal gas constant ( R ) is also positive. Therefore, the slope ( - E _ a R ) must