Chemistry - Chemical Kinetics Question with Solution | TestHub

Reaction 3 is the exact reverse of Reaction 1, so their constants are reciprocals: $K_3=\frac{1}{K_1}⟹{\mathbf{K}}_1\times {\mathbf{K}}_3=1$ (Option A).

Reaction 4 is the exact reverse of Reaction 2, which similarly gives: $K_4=\frac{1}{K_2}⟹{\mathbf{K}}_2\times {\mathbf{K}}_4=1$ (Option D).

Reaction 2 is half of Reaction 1 ($K_2=\sqrt{K_1}$), and Reaction 4 is half of Reaction 3 ($K_4=\sqrt{K_3}$). Substituting these relationships also validates options B and C ($\sqrt{K_1}\times K_4=1$ and $\sqrt{K_3}\times K_2=1$).

Therefore, the correct fundamental direct relations directly matching the options are A and D.