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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3qc163

Which statements about the oxidation of chromium(III) in alkaline hydrogen peroxide are correct?

AThe green chromite/hydroxide species is converted into yellow chromate.
BEach chromium atom loses three electrons.
C $Fe (OH) X_{3}$ dissolves in excess $NaOH$ under the same conditions.
DAdding $Ba X^{2 +}$ to the yellow solution gives a red precipitate of $BaCr X_{2} O X_{7}$ .

Answer: A, B

Cr X^{3 +}

goes to

CrO X_{4} X^{2 -}

(

+ 3

to

+ 6

, 3 electrons per Cr) and the solution turns yellow.

Fe (OH) X_{3}

is not amphoteric and stays as a brown precipitate. Barium ions give yellow

BaCrO X_{4}

, not a red dichromate, in the alkaline solution.

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