JEE PYQ: Chemical Kinetics Question 25
Question 25 - 2020 (08 Jan Shift 2)
Consider the following plots of rate constant versus $\frac{1}{T}$ for four different reactions. Which of the following orders is correct for the activation energies of these reactions?
[Graph shows four lines $a$, $b$, $c$, $d$ with different slopes on a $\log k$ vs $1/T$ plot]
(1) $E_b > E_a > E_d > E_c$
(2) $E_a > E_c > E_d > E_b$
(3) $E_c > E_a > E_d > E_b$
(4) $E_b > E_d > E_c > E_a$
Show Answer
Answer: (3)
Solution
Arrhenius equation: $k = Ae^{-E_a/\text{RT}}$. $\log k = \log A - \frac{E_a}{2.303,R}$. slope $= -\frac{E_a}{2.303,R}$. More negative the slope, greater will be the $E_a$. So correct order is $E_c > E_a > E_d > E_b$.
BETA
