Question

The hybridization states of central atoms of the ion $I_3^ - ,ICl_4^ -$ and $ICl_2^ -$are respectively:
A) $s{p^2},ds{p^2},s{p^3}$
B) $s{p^3}d,s{p^3}{d^2}$ and $s{p^3}d$
C) $s{p^3}d,s{p^3}d,ds{p^2}$
D) $sp,sp,ds{p^2}$

Answer 1

As we know that the central atom which is iodine possess a total of seven electrons and an electronic configuration of $[Kr]4{d^{10}}5{s^2}5{p^5}$ and thus we can say that iodine possess two paired electrons and one unpaired electron in its valence shell.

Complete solution:
As we know that iodine contains two paired electrons and one unpaired electron in its outermost valence shell.
Now, we know that $I_3^ -$ is a linear anion where iodine contains a total of seven electrons and two monovalent atoms and during the combining of iodine with other two iodine atoms the central atom acquires a negative charge of $1$. Thus the hybridization number becomes equivalent to $5$ and therefore, the hybridization becomes $s{p^3}d$.
Similarly, the $ICl_4^ -$ being a neutral compound and according to VSEPR theory, $ICl_4^ -$ is a $A{B_4}{E_2}$ molecule where A is the central atom, B is the bond pair and V is the electron pair. It possesses a total of six electrons with four bonding pairs and two lone pairs of electrons. According to VSEPR theory, it will have $s{p^3}{d^2}$ hybridization with octahedral geometry.
Lastly we have $ICl_2^ -$ and according to VSEPR theory $ICl_2^ -$ is a $A{B_2}{E_3}$ molecule where A is the central atom, B is the bond pair and V is the electron pair. And we know that iodine possesses three lone pairs of electrons and two bond pairs. According to VSEPR theory it will have $s{p^3}d$ hybridization with trigonal bipyramidal geometry.

Therefore,the correct option is (B).

Note: Always remember that the hybridization of any compound is given by mixing of its orbitals of two different atoms and iodine in this case possess a total of seven electrons which are combining with chloride in different manner to form different compounds possessing different hybridization states.