Question

Which of the following ions has resonating structures?
A. `SO_4^(2-)`
B. `PO_4^(3-)`
C. `SO_3^(2-)`
D. All of these

Answer 1

Correct Answer - D
First we write their Lewis structures:
`:underset(..)overset(-..)O-underset( :O: )underset(||)overset( :O: )overset(||)S-underset(..)overset(..-)O:" ":underset(..)overset(-..)O-underset( :O: )underset(||)overset( :O: )overset(||)P-underset(..)overset(..-)O:" " :underset(..)overset(..)O-overset( :O: )overset(||)S-underset(..)overset(..)O:`
In each of these ions, there is more than one reasonable location for a multiple bond. Hence, no single Lewis structure can describe any of these ions. More than one resonance structure must be written for an accurate description.