When \(\mathrm{FeCl}_3\) is added to excess of hot water gives a sol ' \(X\) '. When \(\mathrm{FeCl}_3\) is added to \(\mathrm{NaOH}(a q)\) solution, gives sol ' \(Y\) ' \(X\) and \(Y\) formed in the above processes respectively are

When \(\mathrm{FeCl}_3\) is added to an excess of hot
water, it hydrolyses to form a sol ' \(X\) ' containing \(\mathrm{Fe}_2 \mathrm{O}_3 \cdot x \mathrm{H}_2 \mathrm{O}\) and \(\mathrm{Fe}^{3+}\) ions.
\(\mathrm{FeCl}_2+\mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{Fe}_2 \mathrm{O}_3 \cdot x \mathrm{H}_2 \mathrm{O} \mathrm{Fe}^{3+}+2 \mathrm{Cl}^{-}\)
When \(\mathrm{FeCl}_3\) is added to \(\mathrm{NaOH}(\mathrm{aq})\) solution, a precipitation reaction occurs. The \(\mathrm{Fe}^{3+}\) ions from \(\mathrm{FeCl}_3\) react with \(\mathrm{OH}^{-}\)ions from \(\mathrm{NaOH}\) to form brown precipitate of \(\mathrm{Fe}(\mathrm{OH})_3\). This brown precipitate forms a sol ' \(Y\) ' containing \(\mathrm{Fe}_2 \mathrm{O}_3 \cdot x \mathrm{H}_2 \mathrm{O}\) and \(\mathrm{OH}^{-}\)ions.
\(\mathrm{FeCl}_3+3 \mathrm{NaOH} \longrightarrow \mathrm{Fe}_2 \mathrm{O}_3 \cdot x \mathrm{H}_2 \mathrm{O} / \mathrm{OH}^{-}+3 \mathrm{NaCl}\)