Question

$Fe^{3+} \xrightarrow {SCN^- (\text{excess})}$ Blood red $ (A) \xrightarrow {F^- (excess)}$ Colourless $( B)$
Identify $A$ and $B$.
(i) Write IUPAC name of $A$ and $B$.
(ii) Find out spin only magnetic moment of $B$.

Answer 1

(i) $Fe^{3+} + 3SCN^- \longrightarrow \, \underset {A}{Fe(SCN)_3}$ (blood red colouration)
$ Fe(SCN)_3 + F^- \, \text{(excess)} \, \longrightarrow \, \underset {B}{[FeF_6]^{3-}} + 3SCN^-$
(ii) Magnetic moment $(\mu_S) = \sqrt{n(n + 2)} \, BM$
$ =\sqrt{35} \, BM = 5.92 \, BM.$