For the reaction A $$\to$$ B, the rate constant k(in s^$$-$$1) is given by

$${\log _{10}}k = 20.35 - {{(2.47 \times {{10}^3})} \over T}$$

The energy of activation in kJ mol^$$-$$1 is ____________. (Nearest integer) [Given : R = 8.314 J K^$$-$$1 mol^$$-$$1]

For a first order reaction, the ratio of the time for 75% completion of a reaction to the time for 50% completion is ____________. (Integer answer)

According to the following figure, the magnitude of the enthalpy change of the reaction

A + B $$\to$$ M + N in kJ mol^$$-$$ is equal to ___________. (Integer answer)

The first order rate constant for the decomposition of CaCO₃ at 700 K is 6.36 $$\times$$ 10^$$-$$3s^$$-$$1 and activation energy is 209 kJ mol^$$-$$1. Its rate constant (in s^$$-$$1) at 600 K is x $$\times$$ 10^$$-$$6. The value of x is ___________. (Nearest integer)

[Given R = 8.31 J K^$$-$$ mol^$$-$$1; log 6.36 $$\times$$ 10^$$-$$3 = $$-$$2.19, 10^$$-$$4.79 = 1.62 $$\times$$ 10^$$-$$5]