InterviewSolution
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InterviewSolution
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A mixture consists (A) (red solid) and (B) (colourless solid) which gives lilac colour in flame. (a)Mixture gives black precipitate ( C) on passing H_(2)S (g). (b)( C) is soluble in aquaregia and on evaporation of aquaregia and adding SnCl_(2) gives greyish black precipitate (D). The salt solution with NH_(4)OH gives a brown precipitate. (i)The sodium extract of the salt with C Cl_(4)//FeCl_(3) gives a violent layer. (ii)The sodium extract gives yellow precipitate with AgNO_(3) solution which is insoluble in dilute ammonia solution. Identify (A) and (B), and the precipitates (C ) and (D). |
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Answer» (a)`(A)+(B)overset(H_(2)S(g))to(C)` BLACK precipitate. (b)`( C)underset("in aque regia")overset("soluble")to "soluble"overset("EVAPORATION")to"Residue"overset(SnCl_(2))to"Greyish black precipitate"(D)` `(A)+(B) overset(NH_(4)OH)to` brown precipitate.So second cation may be `Hg^(2+)` (i)Sodium carbonate extract of salt `overset(C Cl_(4)//FeCl_(3)) to` violent colour. (ii)Sodium extract of salt `overset(AgNO_(3))to "yellow precipitate" overset(NH_(3))to` soluble. So the anion may be `I^(-)` (a)`HgI_(2)+H_(2)Sto HgS (C )darr("black")+2HI` (b)`3HgS+6HCl+2HNO_(3)to3HgCl_(2)+2NO+4H_(2)O+S` `HgCl_(2)+SnCl_(2) to Hg darr (D) ("greyish black")+SnCl_(4)` `2KI(B)+HgI_(2)(A)toK_(2)[HgI_(4)]`(orange) `2K_(2)[HgI_(4)]+NH_(3)+3KOH to [HgOHg(NH_(2))I]darr`(brown) Sodium carbonate extract of salt contains `NaI` `2NaI+2Fe^(3+)overset(C Cl_(4))toI_(2)uarr("violet")+2Na^(+)+2Fe^(2+)` `I_(2)` dissolves in `C Cl_(4)` givingviolet colour solution. `AgNO_(3)+NaI toAgI darr("yellow")+NaNO_(3)` `AgI` is insoluble in ammonia solution. So,`(A),(B),( C)` and `(D)` are `HgI_(2),KI,HgS` and `Hg` respectively. `Mg^(2+)+2HCO_(3)^(-)`(from sodium salt)`toMg(HCO_(3))_(2)`(solube)`overset(Delta)toMgCO_(3)darr` (white)`+H_(2)O+CO_(2)` `Hg^(2+)` gives red precipitate of `Hgl_(2)` which dissolves in excess `KI`forming colourless `[Hgl_(4)]^(-)`(orange solution) `Pb^(2+)` gives yellow precipitate of `Pbl_(2).Cu^(2+)` gives white precipitate of `Cu_(2)I_(2)` with evolution of iodine. `[Zm(OH)_(4)]^(2-)overset(H_(2)O-"boiled")toZn(OH)_(2)darr("white")+2OH^(-)` `Zn(OH)_(2)` precipitate is readily soluble in excess of ammonia and in solutions of ammonium salts due to the formation of tetraamminezinc`(II)`. |
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