question_answer

\[100\text{ }mL\]of \[0.3\,M\] \[F{{e}^{3+}}(aq)\] (aq) ions were electrolysed by a charge of\[0.072\text{ }F\]. In electrolysis, metal was deposited and \[{{O}_{2}}(g)\] was evolved. At the end of electrolysis, it is desired to oxidize the un-electrolyzed metal ion. \[F{{e}^{3+}}+{{e}^{\bigcirc -}}\xrightarrow{{}}F{{e}^{2+}}\] \[F{{e}^{2+}}+2{{e}^{\bigcirc -}}\xrightarrow{{}}Fe\] The moles of \[F{{e}^{2+}}\] ions left unelectrolysed in the solution is ______.

Answer:

0.09