What is the number of unpaired electrons in the $NO$ molecule?

Consider the given figure showing the formation of $H^{+}_2$ ion depending on internuclear distance versus potential energy of the system.
Which is the correct statement?

In which of the following molecules do the $\pi 2p_x$ and $\pi 2p_y$ orbitals fill after the $\sigma 2p_z$ molecular orbital?

Which of the following statements is incorrect when $C_2$ changes to $C_2^{2-}$?

The linear combination of atomic orbitals to form molecular orbitals takes place only when the combining atomic orbitals:
$A$. have the same energy
$B$. have the minimum overlap
$C$. have same symmetry about the molecular axis
$D$. have different symmetry about the molecular axis
Choose the most appropriate from the options given below:

The correct sequence of bond order is