The $d_{xy}$ orbital can form a $\pi$ bond with another $d_{xy}$ orbital along which axis?

$A$ carbon-carbon triple bond in ethyne $(HC \equiv CH)$ consists of:

Why does the type of overlap shown in the following figure not result in bond formation? Explain.

Which of the following is correct for the $N_2$ triple bond?

Which of the following orbital combinations form a sigma $(\sigma)$ bond? $1s-1s, 2s-2s, 1s-2s, 2p_x-2p_x, 2p_y-2p_y, 2p_z-2p_z$.

Given below are two statements :
Statement $(I)$ : The oxidation state of an element in a particular compound is the charge acquired by its atom on the basis of electron gain enthalpy consideration from other atoms in the molecule.
Statement $(II)$ : $p\pi-p\pi$ bond formation is more prevalent in second period elements over other periods.
In the light of the above statements,choose the most appropriate answer from the options given below :