In the sequence of reactions Fe^(3+) (aq) underset(SCN^(-))overset("Excess of")rarr underset(("A"))("Blood red colour")underset(F^(-))overset("Excess of")rarr underset(("B"))("Colourless") Identify A and B. Write their IUPAC names. Explain the hybridisation involved in B and calculate spin only magnetic moment of B.

In the sequence of reactions Fe^(3+) (aq) underset(SCN^(-))overset("E

1.	In the sequence of reactions Fe^(3+) (aq) underset(SCN^(-))overset("Excess of")rarr underset(("A"))("Blood red colour")underset(F^(-))overset("Excess of")rarr underset(("B"))("Colourless") Identify A and B. Write their IUPAC names. Explain the hybridisation involved in B and calculate spin only magnetic moment of B.
Answer» Solution :`Fe^(3+)(AQ)+3SCN^(-)rarr underset("Trithiocyanato IRON (III)")underset(("A"))underset("Blood RED colour")([Fe(SCN)_(3)])underset(F^(-))overset("Excess of")rarr underset("Hexafluoridoferrate (III)")underset(("B"))underset("Colourless")([FeF_(6)]^(3-))` Hybridisation in `[FeF_(6)]^(3-)=sp^(3)d^(2) "" (becauseF^(-) " is a weak ligand")` In `[FeF_(6)]^(3-), Fe^(3+)` has the configuration `3d^(5)`, i.e., it has 5 unpaired electrons. `THEREFORE` Magnetic moment `= sqrt(n(n+2))=sqrt(5(5+2))=sqrt(35)=5.92` BM.