Question

In $P{O}_4^{3-}$ ion, the formal charge on each oxygen atom and $P-O$ bond order respectively are

• A. -0.75, 1.0
• B. -3, 1.25
• C. -0.75, 0.6
• D. -0.75, 1.25

Answer 1

The correct option is D -0.75, 1.25


There are four resonating structures. The formal charge is sum of total charge on one oxygen atom in all the given structures divided by the number of resonating structures. Thus, it is $-\frac{3}{4}$ i.e. $-0.75$.
The average bond order is given by sum of total number of bonds in all the resonating structures for an atom divided by the number of resonating structures. Here, for any oxygen atom, there are total $5$ bonds in all $4$ resonating structures. So, the bond order is: $\frac{5}{4}$ i.e. $1.25$.