Let's analyze both statements to determine their correctness.
Considering the analysis for both statements, the most appropriate choice is: Statement I is incorrect but Statement II is correct.
Explanation:
1. Statement (I): Incorrect. - The oxidation state of an element is not determined based on electron gain enthalpy. Instead, it is based on the number of electrons lost, gained, or shared during bond formation.
2. Statement (II): Correct. - \( p\pi-p\pi \) bond formation is more common in second-period elements (e.g., \( C, N, O \)) due to their small size and effective overlap of \( p \)-orbitals, which diminishes in larger elements from lower periods.
Final Answer is Option (4).
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)

Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)