The following reaction can be conducted as a titration in liquid BrF5: a. T...

a.

Solvent \(\mathrm{BrF}_{5}\) autodissociates as follows:

\(2 \mathrm{BrF}_{5} \rightleftharpoons\left[\mathrm{BrF}_{4}\right]^{+}+\left[\mathrm{BrF}_{6}\right]\)

So fill the cation and anion in the reaction of titration as follows:

\(2 \mathrm{Cs}\left[\mathrm{BrF}_{6}\right]^{-}+\left[\mathrm{BrF}_{4}\right]^{+}\left[\mathrm{Sb}_{2} \mathrm{~F}_{11}\right]^{-} \rightarrow 3 \mathrm{BrF}_{5}+2 \mathrm{CsSbF}_{6}\)

Hence, ions in the brackets are \(\mathrm{BrF}_{6}^{-}\) and \(\mathrm{BrF}_{4}^{+}\).

b.

The cation is \(\mathrm{BrF}_{4}^{+}\) and anion is \(\mathrm{BrF}_{6}^{-}\).

\(\mathrm{BrF}_{4}^{+}\) has the point group \(C_{2 v}\). It has \(\mathrm{E}\) the identity operation, \(\mathrm{C}_{2}\) a twofold symmetry axis which passes from Br atom, \(\sigma_{v}\) is the first mirror plane which contains the \(\mathrm{C}_{2}\) axis and is the

molecular plane, \(\sigma_{v}^{\prime}\) is the second mirror plane which is perpendicular to \(\sigma_{y}\) and contains \(\mathrm{C}_{2}\) axis.

\(\mathrm{BrF}_{6}^{-}\) anion has octahedral shape (distorted), so the point group is \(\mathrm{O}_{\mathrm{h}} .\)

Hence, point group of cation \(\mathrm{BrF}_{4}^{+}\) is \(C_{2 v}\) and point group of anion \(\mathrm{BrF}_{6}^{-}\) is \(O_{\mathrm{h}}\).

c.

According to solvent-system concept, cation formed by the autodissociation of a solvent acts as an acid. Solvent \(\mathrm{BrF}_{5}\) autodissociates as follows:

\(2 \mathrm{BrF}_{5} \rightleftharpoons\left[\mathrm{BrF}_{4}\right]^{+}+\left[\mathrm{BrF}_{6}\right]\)

Hence, cation \(\mathrm{BrF}_{4}^{+}\) serves as an acid.