In the electronic structure of acetic acid $(CH_3COOH)$,there are:

With what neutral molecule is $ClO^{-}$ isoelectronic? Is that molecule a Lewis base?

Which of the following statements is true with respect to $H_2O$,$NH_3$ and $CH_4$?
$A.$ The central atoms of all the molecules are $sp^3$ hybridized.
$B.$ The $H-O-H$,$H-N-H$ and $H-C-H$ angles in the above molecules are $104.5^{\circ}$,$107.5^{\circ}$ and $109.5^{\circ}$ respectively.
$C.$ The increasing order of dipole moment is $CH_4 < NH_3 < H_2O$.
$D.$ Both $H_2O$ and $NH_3$ are Lewis acids and $CH_4$ is a Lewis base.
$E.$ $A$ solution of $NH_3$ in $H_2O$ is basic. In this solution,$NH_3$ and $H_2O$ act as a Lowry-Bronsted base and acid respectively.
Choose the correct answer from the options given below:

Amongst the following,the total number of species $NOT$ having $8$ electrons around the central atom in its outermost shell is $NH_3$,$AlCl_3$,$BeCl_2$,$CCl_4$,$PCl_5$:

Which of the following sets are correctly matched?

Molecule	Number of lone pairs of electrons on central atom	Hybridization
$I. PCl_3$	$1$	$sp^3$
$II. SO_2$	$1$	$sp^2$
$III. SF_4$	$1$	$sp^3d$
$IV. ClF_3$	$2$	$sp^3d$

In the solid state,$PCl_5$ exists as which of the following?