Using the data provided, calculate the multiple bond energy (kJ mol^$$-$$1) of a C=C bond in C₂H₂. That energy is (take the bond energy of C-H bond as 350 kJ mol^$$-$$1).

$$\matrix{ \hfill {2C(s) + {H_2}(g) \to {C_2}{H_2}} & \hfill {\Delta H = 225\,kJ\,mo{l^{ - 1}}} \cr \hfill {2C(s) \to 2C(g)} & \hfill {\Delta H = 1410\,kJ\,mo{l^{ - 1}}} \cr \hfill {{H_2}(g) \to 2H(g)} & \hfill {\Delta H = 330\,kJ\,mo{l^{ - 1}}} \cr } $$

Match the transformations in column I with appropriate options in column II

Column I
(A) CO₂(s) $$\to$$ CO₂(g)
(B) CaCO₃(s) $$\to$$ CaO(s) + CO₂(g)
(C) 2H $$\to$$ H₂(g)
(D) P_{(white, solid)} $$\to$$ P_{(red, solid)}

Column II
(p) phase transition
(q) allotropic change
(r) $$\Delta H$$ is positive
(s) $$\Delta S$$ is positive
(t) $$\Delta S$$ is negative

The bond energy (in kcal mol^-1) of a C-C single bond is approximately

The species which by definition has ZERO standard molar enthalpy of formation at 298 K is