$$F{e^{3 + }}\buildrel {SN{C^ - }(excess)} \over \longrightarrow $$ blood red $$F{e^{3 + }}\buildrel {SN{C^ - }(excess)} \over \longrightarrow $$ colourless (B):

(A) Identify compound A and B and write their IUPAC names.

(B) Determine the spin only magnetic moment of B.

In the following reaction sequence, M is a transition metal.

Identify the metal M and MCl$$_4$$. Explain the difference in colours of MCl$$_4$$ and A.