Which of the following statements is incorrect regarding $SO_3$?

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

If compound $MX_4$ is non-polar and has no lone pair at the central atom,then the bond angle $\angle XMX$ in the compound may be:

In the reaction $AlCl_3 + Cl^- \rightarrow [AlCl_4]^-$,$AlCl_3$ acts as a.......

Which one of the following is not correct for the reaction given below:
$NH_3 + BF_3 \to NH_3.BF_3$

Which of the following formulas does not correctly represent the bonding capacity of the atom involved?