In chromyl chloride test for confirmation of Cl – ion, a yellow solution is obtained. Acidification of the solution and addition of amyl alcohol and 10 % H 2 O 2 turns organic layer blue indicating fo

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In chromyl chloride test for confirmation of Cl – ion, a yellow solution is obtained. Acidification of the solution and addition of amyl alcohol and 10 % H 2 O 2 turns organic layer blue indicating formation of chromium pentoxide. The oxidation state of chromium in that is

TestHub · Accepted Answer

The chromyl chloride test is used to detect chloride ions in the qualitative analysis. If any chloride salt like sodium chloride is heated with acidified potassium dichromate it produces red colour fumes of chromyl chloride. It confirms the presence of chloride ions in that salt.

${Cl}^{-} + K_{2} {Cr}_{2} O_{7} + H_{2} {SO}_{4} \to {CrO}_{2} {Cl}_{2} \overset{Basic medium}{\to} \underset{yellow solution}{{CrO}_{4}^{2 -}} + {Cl}^{-}$

Chromate reacts rapidly with hydrogen peroxide to exchange two oxo ligands and become diperoxochromate(VI)

$\underset{yellow solution}{{CrO}_{4}^{2 -}} \to_{3 . 10 % H_{2} O_{2}}^{\begin{matrix} 1 . Acidification \\ 2 . Amyl alcohol \end{matrix}} \underset{blue compound}{{CrO}_{5}}$

Hence, the answer is option A.

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