Question

what is the bond order of the s - o bonds in the following?
a. 1.00
b. 1.33
c. 1.50
d. 1.75
e. 2.00

Explanation:

Step1: Identify resonance structures

There are 3 resonance - contributing structures for the $SO_{3}^{2 - }$ ion shown.

Step2: Calculate bond order formula

The formula for bond order in case of resonance is $\text{Bond Order}=\frac{\text{Total number of bonding pairs}}{\text{Number of equivalent bonds}}$.
In the resonance structures of $SO_{3}^{2 - }$, the total number of bonding pairs between S and O is 4 (counting all the double - bond and single - bond contributions in the resonance forms), and the number of equivalent S - O bonds is 3.

Step3: Calculate bond order

$\text{Bond Order}=\frac{4}{3}\approx1.33$.

Answer:

B. 1.33