The correct structures of A and B formed in the following reactions are :

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]

The number of optical isomers possible for [Cr(C₂O₄)₃]^3$$-$$ is ____________.

Two flasks I and II shown below are connected by a valve of negligible volume.


When the valve is opened, the final pressure of the system in bar is x $$\times$$ 10^$$-$$2. The value of x is __________. (Integer answer)

[Assume - Ideal gas; 1 bar = 10⁵ Pa; Molar mass of N₂ = 28.0 g mol^$$-$$1; R = 8.31 J mol^$$-$$1 K^$$-$$1]