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 yel
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.
1 Answers
(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)`