The maximum number of atoms that can be in one plane in the molecule $p$-nitrobenzonitrile are

$A$ tin chloride $Q$ undergoes the following reactions (not balanced):
$Q + Cl^{-} \rightarrow X$
$Q + Me_3N \rightarrow Y$
$Q + CuCl_2 \rightarrow Z + CuCl$
$X$ is a monoanion having pyramidal geometry. Both $Y$ and $Z$ are neutral compounds. Choose the correct option$(s)$.
$(1)$ The central atom in $X$ is $sp^3$ hybridized
$(2)$ The oxidation state of the central atom in $Z$ is $+4$
$(3)$ The central atom in $Z$ has no lone pair of electrons
$(4)$ There is a coordinate bond in $Y$

Which of the following behave as Lewis acids: $BF_3, SnCl_2, SnCl_4$?

The correct order of bond strength for the given species is:

The octet rule is not valid for which of the following molecules?

Which of the statements given below is incorrect?