Chapter 8, Problem 87A

Interpretation Introduction

Interpretation:

From the following molecules order of shortest to longest sulfur-oxygen needs to be identified.

$\text{a}\text{.}{\text{SO}}_2$  $\text{b}{\text{. SO}}_3^2$  $\text{c}{\text{. SO}}_4^{2-}$

Concept introduction:

The strength of a covalent bond depends on the distance between the bonded nuclei. Bond length is the distance between the maximum attractions of $2$ bonded nuclei. It depends on the bonding atoms’ size and electron pairs they share.

Answer to Problem 87A

Order of shortest to longest sulfur-oxygen bond of the given molecule is as follows:

$\text{a}\text{.}{\text{SO}}_2$, $\text{c}{\text{. SO}}_4^{2-}$, $\text{b}{\text{. SO}}_3^{2-}$

Explanation of Solution

Bond length of S-O is determined by the multiple and single bonds number which contribute to the resonance structure. Among the given molecules, ${\text{SO}}_2$ have two double bonds, ${\text{SO}}_4^{2-}$ have two double bonds and two single bonds and ${\text{ SO}}_3^{2-}$ have one double bond and two single bonds. Bond length of ${\text{SO}}_2$ is shorter than ${\text{SO}}_4^{2-}$ and ${\text{SO}}_4^{2-}$ is shorter than ${\text{ SO}}_3^{2-}$. Hence, order of shortest to longest sulfur-oxygen bond is as follows: $\text{a}\text{.}{\text{SO}}_2$, $\text{c}{\text{. SO}}_4^{2-}$, $\text{b}{\text{. SO}}_3^{2-}$

Conclusion

Bond length is the characteristic of a chemical bond. Depending on the molecule it contains, bonds differ from one atom to another.