question_answer 49)

  In \[PO_{4}^{3-}\] ion, the formal charge on the oxygen atom of P- O bond is : (a) +1                                    (b)  -1                                    (c) -0.75                                (d) +0.75

Answer:

  (b) Formal charge of the atom in the molecule or ion =(Number of valence electrons in free atom) - (Number of lone pair electrons + \[\frac{1}{2}\] Number of bonding electrons) Formal charge on oxygen = \[6-\left( 6+\frac{1}{2}\times 2 \right)=6-7=-1\]