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How many of the given statements are true for potash alum. (1) it is a white crystalline solid (2) it swells up on heating (3) it imparts a golden yellow colour to the bunsen flame (4) An aqueous solution of the above given a white gelatinous precipitate with BaCl_(2) solution soluble only in concentrated sulphuric acid. (5) An aqueous solution of the above given a white gelatinous precipitate on treatment with NH_(4)OH. Which dissolves in aqueous NaOH in excess and reappears, On boiling with concentrated NH_(4)Cl solution. (6) It gives a yellow precipitate with Cobalt nitrile solution. (7) White precipitate in 5^(th) state can also be obtained by passing H_(2)S gas in aqueous solution of the above. |
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Answer» Solution :(1)`K_(2)SO_(4)Al_(2)(SO_(4))_(3)` is a white crystaline solid. (2)upon HEATING it swells up DUE to the evolution of water MOLECULES. `K_(2)SO_(4)Al_(2)(SO_(4))_(3).24H_(2)O overset(Delta)toK_(2)SO_(4)Al_(2)(SO_(4))_(3).24H_(2)O` (3)because of presence of potassium it imparts.Voilet color to bunsen flame. (4)`Ba^(2+)+SO_(4)^(2-)to underset("whiteppt.")(BaSO_(4)darr` `BaSO_(4)+H_(2)SO_(4) to Ba(HSO_(4))_(2)` Soluble (5)`Al^(3+)+30H^(-)to underset("white")(Al(OH)_(3))darr overset(NaOH)to underset("soluble")(NaAeO_(2)) overset(NH_(4)Cl)to Al(OH)_(3) darr` (6)`4K^(+)+[CO(NO_(2))_(6)]^(4+)to underset("yellow ppt")(K_(4)[CO(NO_(2))_(6)])` (7)`2AL^(3+)+3S^(-2)to Al_(2)S_(3)underset("Hydrolysis")overset(H_(2)O)to underset("whiteppt.")(Al(OH)_(3) darr)` |
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