Question

Consider the given reaction. The rate constant for two parallel reactions were found to be $\times {10}^{-2}{{dm}^3{mol}^{-1}s}^{-1}$ and $4\times {10}^{-2}{{dm}^3{mol}^{-1}s}^{-1}$. If the corresponding energies of activation of the parallel reaction are $100$ and $120kJ/mol$ respectively, what is the net energy of activation ($E_a$) of $A$?

• A. $100kJ/mol$
• B. $120kJ/mol$
• C. $116kJ/mol$
• D. $220kJ/mol$

Answer 1

The correct option is C $116kJ/mol$

Net energy of activation ($E_a$) of $A$ is $K_1\times \frac{E_{a1}}{K_{av}}+K_2\times \frac{E_{a2}}{K_{av}}=\frac{1}{4}\times 100+\frac{4}{5}\times 120=116kJ/mole$