Select the correct statement(s) about potash alum, $KAl (SO X_{4}) X_{2} \cdot 12 H X_{2} O$ .

AIts aqueous solution is acidic.
BIts solution gives a white precipitate with $BaCl X_{2}$ that is insoluble in dilute HCl.
CIt is used as a coagulant in water purification.
DIt is a complex salt and its solution does not give the tests of $K X^{+}$ or $Al X^{3 +}$ ions.

Answer: A, B, C

Hydrolysis of

[Al (H X_{2} O) X_{6}] X^{3 +}

makes the solution acidic, so A is true. The gelatinous

Al (OH) X_{3}

formed adsorbs and coagulates suspended impurities, so B is true.

Ba X^{2 +} + SO X_{4} X^{2 -} BaSO X_{4}

, which is insoluble in dilute acid, so C is true. An alum is a double salt that dissociates completely in water and shows the tests of all its ions, so D is false.

Practice p-Block Elements: Groups 13 and 14 More on Aluminium compounds and alums

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Select the correct statement(s) about potash alum, KAl(SOX4​)X2​⋅12HX2​O.

Answer: A, B, C

More questions on Aluminium compounds and alums

Select the correct statement(s) about potash alum, $KAl (SO X_{4}) X_{2} \cdot 12 H X_{2} O$ .