question_answer

In \[PO_{4}^{3-}\] ion, the formal charge on each oxygen atom and \[P-O\] bond order respectively are: [AIPMT 1998]

A)        \[-\text{ }0.75,\text{ }0.6\]        

B)       \[-\text{ }0.75,\text{ }1.0\]        

C)  \[-\text{ }0.75,\text{ }1.25\]

D)      \[-\text{ }3,\text{ }1.25\]

Correct Answer: C

Solution :

           

Bond order between \[P-O\]

\[=\frac{\text{no}\text{. of bonds in all possible direction}}{\text{Total no}\text{. of resonating structure}}\]

\[=\frac{5}{4}=1.25\]

Resonating structures are :

Total charge on \[PO_{4}^{3-}\] ion is \[-3\].

So, the average formal charge on each \['O'\] atom is \[=-\frac{3}{4}=-0.75\]