The rate constant, k for a first order reaction, $ \text{C}_2\text{H}_5\text{I}(g) \rightarrow \text{C}_2\text{H}_4(g) + \text{HI}(g) $ is $ x \, \text{s}^{-1} $ at 600 K and $ 4x \, \text{s}^{-1} $ at 700 K. The energy of activation of the reaction (in kJ mol$ ^{-1} $) is (log 4 = 0.6, R = 8.3 J K$ ^{-1} $ mol$ ^{-1} $)