Which of the following is not a Lewis acid?

$A$ conducting rod $AC$ of length $4l$ is rotated about a point $O$ in a uniform magnetic field $\vec{B}$ directed into the paper. $AO = l$ and $OC = 3l$. Then:

Assign $A, B, C, D$ from the given type of reaction.
$HgI_2 \downarrow + 2KI \rightleftharpoons K_2[HgI_4]$

If $x$ is small,so that $x^2$ and higher powers can be neglected,then the approximate value for $\frac{(1-2 x)^{-1}(1-3 x)^{-2}}{(1-4 x)^{-3}}$ is

Which of the following fluorides of Xenon is impossible?

If $3$ is a root of $x^2+kx-24=0$,then it is also a root of which of the following equations?