Question

Assertion: $SeC{l_4}$​ does not have a tetrahedral structure.
Reason: $Se$ in $SeC{l_4}$ has two lone pairs.
A.Both Assertion and Reason are true and Reason is the correct explanation for Assertion
B.Both Assertion and Reason are true but Reason is not the correct explanation for Assertion
C.Assertion is true but Reason is false
D.Both Assertion and Reason are false
E.Assertion is false but Reason is true

Answer 1

Selenium tetrachloride is an inorganic compound with the formula $SeC{l_4}$. The compound exists as a yellow to white volatile solid. It is prepared by treating selenium with chlorine. This molecule is an excellent example of a situation where maximal bonding cannot be achieved with the simplest molecular formula.

Complete step by step answer:
In a tetrahedral molecule, there's one central atom bonded to four surrounding atoms, with no lone pairs of electrons.
$SeC{l_4}$ possesses a distorted trigonal pyramid geometry. Here, $\,Se\,$ has only one lone pair of electrons then, it is $\,s{p^3}d\,$ hybridized.
$SeC{l_4}$ possesses a see-saw geometry, which could be considered a distorted trigonal bipyramidal structure having one lone pair (lp) of electrons within the basal position of the trigonal bipyramidal. See-saw geometry of $SeC{l_4}$ molecules arises due to the $\,s{p^3}d\,$ hybridization of the central atom. The distortion in shape is because of the presence of a lone pair of electrons.
The $SeC{l_4}$ molecule is a polar molecule since it has a lone pair of nonbonding electrons within the valence shell of the selenium atom and it interacts with the bonding pairs of electrons, thereby creating a spatial asymmetry of the dipole moments of the polar $\,Se - Cl\,$ bonding. The result is a $SeC{l_4}$ molecule with a net moment.
So the correct answer is option C).

Note: In chemistry, a lone pair is noted as a pair of valence electrons that shall not be shared with another atom in an exceedingly very bond and is usually called an unshared pair or non-bonding pair. Lone pairs are found within the outermost grouping of the atoms. they'll be easily identified by employing a Lewis structure. A trigonal pyramid may be a molecular geometry with one atom at the apex and three atoms at the corners of a trigonal base, resembling a tetrahedron but it shall not be confused with the tetrahedral geometry.