Which statements about the tests for Al^3+ are correct?

NH4OH with NH4Cl gives a white gelatinous precipitate of Al(OH)3.

Al(OH)3 adsorbs aluminon to give a red lake.

Al(OH)3 dissolves in excess NaOH as [Al(OH)4]- and is re-precipitated on adding NH4Cl and boiling.

NH4OH with NH4Cl gives a white gelatinous precipitate of Al(OH)3.

The precipitate dissolves in excess NH4OH forming [Al(NH3)6]^3+.

Al(OH)3 adsorbs aluminon to give a red lake.

Al(OH)3 dissolves in excess NaOH as [Al(OH)4]- and is re-precipitated on adding NH4Cl and boiling.

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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3qc162

Which statements about the tests for $Al X^{3 +}$ are correct?

A $NH X_{4} OH$ with $NH X_{4} Cl$ gives a white gelatinous precipitate of $Al (OH) X_{3}$ .
BThe precipitate dissolves in excess $NH X_{4} OH$ forming $[Al (NH X_{3}) X_{6}] X^{3 +}$ .
C $Al (OH) X_{3}$ adsorbs aluminon to give a red lake.
D $Al (OH) X_{3}$ dissolves in excess $NaOH$ as $[Al (OH) X_{4}] X^{-}$ and is re-precipitated on adding $NH X_{4} Cl$ and boiling.

Answer: A, C, D

Al (OH) X_{3}

is white and gelatinous, insoluble in excess ammonia (no stable ammine in water), adsorbs aluminon to give a red lake, and dissolves in excess alkali as

[Al (OH) X_{4}] X^{-}

. Adding

NH X_{4} X^{+}

lowers the pH, giving back

Al (OH) X_{3}

, so B is the only false statement.

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Which statements about the tests for AlX3+ are correct?

Answer: A, C, D

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Which statements about the tests for $Al X^{3 +}$ are correct?