Question

Structure of ${S_2}C{l_2}$ is analogous to which of the following?
(A) $SOC{l_2}$
(B) $C{O_2}$
(C) ${H_2}S$
(D) ${H_2}{O_2}$

Answer 1

Find out the valency of ${S_2}C{l_2}$ i.e. Disulfur dichloride and with this valancy find its structure that is the most stable. Similarly, the valencies and structures of the given compounds can be found out. The elements that resemble the most with Sulfur and Chlorine will have a similar structure.

Complete answer: In the given molecule ${S_2}C{l_2}$ we know that the valency of Chlorine is seven and it needs one electron to complete its valency. Sulfur has $6$ electrons in the valence shell. Therefore its valency is six and it requires two electrons to attain inert gas valency.
With this information, it is clear to us that each Sulfur forms a bond with one Chlorine and there also exists a $S - S$ bond.
We can write the structure for ${S_2}C{l_2}$ as $Cl - S - S - Cl$
We have already established that Sulfur has six valence electrons, meaning that after two bonds it will have four remaining paired electrons i.e. lone pairs. To minimize the electron repulsions, the molecule forms a structure where the angle between the chlorine atoms is $90^\circ$.
This structure is known as Gauche. The molecule ${H_2}{O_2}$ also forms the same structure.

Therefore the structure of ${S_2}C{l_2}$ is analogous to ${H_2}{O_2}$ i.e. option (D).

Note: We find out the structure of ${S_2}C{l_2}$ and to do that we first find the valencies of Sulfur and Chlorine. We then check for the number to lone pairs on the central atom(s) i.e. sulfur. With this information, we can find out the structure of ${S_2}C{l_2}$ and similarly we check for the compound that has an analogous structure to ${S_2}C{l_2}$ which is Hydrogen peroxide.