(a) In a polar solvenbt , PCl_(5) undergoes an ionization reaction as follows :2 PCl_(5)hArrPCl_(4)^(+) + PCl_(6) ^(-) Wht will be the geometrical shape of each species present In the equalilbrium maxture ? (b) Why doesPCl_(5) exist as[ PCl_(4)]^(+) [PCl_(6)]^(-) ?

(a) In a polar solvenbt , PCl_(5) undergoes an ionization reaction as

1.	(a) In a polar solvenbt , PCl_(5) undergoes an ionization reaction as follows :2 PCl_(5)hArrPCl_(4)^(+) + PCl_(6) ^(-) Wht will be the geometrical shape of each species present In the equalilbrium maxture ? (b) Why doesPCl_(5) exist as[ PCl_(4)]^(+) [PCl_(6)]^(-) ?
Answer» Solution :`X = (1)/(2) [{{:(" NO of valence electrons "),("of the central atom "):}}+{{:(" NO of monovalent atoms/group "),("surrounding the central atom "):}}]` `- {{:("Charge on the cation if the given "),(" SPECIES is a polyatomic cation "):}}+{{:(" Charge on the anion if the given "),(" species is a polyatomic anion"):}}` For `PCl_(5), X = (1)/(2) [5 + 5] - 0 + 0 = 5(sp^(3) d ,`bipyramidal) For`PCl_(4_^(+) , X = (1)/(2) [ 5 + 4 - 1 + 0 ] = 4 (sp^(3), `tetrahedra) For ` PCl_(6) ^(-), X = (1)/(2) [ 5 + 6 - 0 + 1] = 6 (sp^(3) d^(2)` , octahedral) (B) ` PCl_(5)` has DIFFERENT axial and equatorial bohnd lengths and THEREFORE , has an unsymmetrical structure Which is not stable . By dissociation, it changes into tetrahedral ` ([PCl_(4)]^(+)` and octahedral`[PCl_(6)]^(-)` Which are stable .