Consider the following plots of log of rate constant k (log k) vs 1T for three different reactions. The correct order of activation energies of these reactions is : [figure]
- Ea2 > Ea1 > Ea3
- Ea1 > Ea3 > Ea2
- Ea3 > Ea2 > Ea1
- Ea1 > Ea2 > Ea3
Answer
(1) Ea2 > Ea1 > Ea3
Solution
Arrhenius equation: k = A e-Ea/RT
k = A - Ea2.303 R 1T
Slope of log k vs 1T = - Ea2.303 R, i.e. the steeper the line, the larger the activation energy.
From the graph, steepness: line 2 (almost vertical) > line 1 > line 3 (almost flat).
Ea2 > Ea1 > Ea3
Answer: (1)