Number of $S-S$ bonds in $H_2S_nO_6$ is:

Which of the following species has polar and non-polar bonds but the molecule as a whole is non-polar?

Which of the following compounds is polar and has a central atom with $sp^2$ hybridization?

Identify the correct statement$(s)$ from the following:
$a$) Dipole moment of $NH_3$ is more than $NF_3$
$b$) $SF_4$ is square planar
$c$) $SnCl_4$ is more covalent than $SnCl_2$
$d$) $In_2SO_4$ sulphur atom has expanded octet

The incorrect order is

Which of the following consists of an equal number of $p\pi - p\pi$ and $p\pi - d\pi$ bonds?