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IIT Chemistry Sample Paper 1

Inorganic

  1. An aq soln of a gas X gives the fol reactions:
    1. It decolorizes an acidified soln of K 2 Cr 2 O 7
    2. On boiling it with H 2 O 2 , cooling it and then adding an aq soln of BaCl 2 a ppt insoluble in dil HCl is obtained.
    3. On passing H 2 S a white turbidity is obtained.
    Identify X and give all reactions taking place.
  2. The gas liberated on heating a mix of 2 salts with NaOH gives a reddish brown ppt with an alk soln K 2 HgI 4 . The soln (aq) of the mix on treatment with BaCl 2 gives a white pt which is sparingly solution in conc HCl. On heating the mix with K 2 Cr 2 O 7 and conc H 2 SO 4 red vap of A are produced. The aq soln of the mix gives a deep blue coloration B with pot ferricyanide soln. Identify the radicals and write balanced eqns for formation of A and B?
  3. A black colored compd A on reaction with dil H 2 SO 4 gives a gas B which on passing in a soln of an acid C gives a white turbidity D. Gas B when passed thro acidified soln of E gives a ppt F solution in dil HNO 3 . After boiling this soln when an excess of ammonium hydroxide is added a blue colored compd G is formed. To this soln on addn of acetic acid and aq pot ferrocyanide a chocolate ppt H is obtained. On addn of an aq soln of E a white ppt insol in HNO 3 is obtained. Identify A to H.
  4. A mix of 2 salts were treated as follows:
    1. The mix was heated with manganese dioxide and conc H 2 SO 4 when yellowish green gas was obtained.
    2. The mix on heating with sod hydroxide soln gave a gas, which turned red litmus blue.
    3. Its soln in water gave blue ppt with pot ferricyanide and red coloration with amm thiocyanate.
    4. The mix was boiled with pot hydroxide and the liberated gas was bubbled thro an alk soln of K 2 HgI 4 to give brown pt.
    Identify the 2 salts. Give ionic reactions for the tests (i) to (iii).
  5. A certain inorganic compd A on heating loses its water of crystallization. On further heating a blackish powder B and 2 oxides of S - C and D are obtained, the powder B on boiling with HCl gives a yellow soln E. When H 2 S is passed thro E a white turbidity F and apple green soln G are obtained. The soln E on treatment with thiocyanate ions gives a blood red color compd H. Identify A to H.
  6. A green colored metallic chloride A when treated with sod hydroxide and H 2 O 2 gives a yellow soln due to the formation of compd B. The color of this soln changes to orange when dil H 2 SO 4 is added to it. It is due to the formation of compd C. When KCl is heated along with C in presence of conc H 2 SO 4 a red volatile liq D is formed. The compd C when treated with amm chloride forms compd E which decomposes on heating giving a colorless gas F water and green residue G. When Mg is burnt in the presence of F a white solid H is formed. The latter on hydrolysis forms a gas I which gives white fumes with HCl. Identify A to I giving involved eqns.
  7. Your are given a white material which could be any of the following :
    ZnO, ZnCO 3 , Zn(OH) 2 , ZnS, Zn(NH 3 ) 4 Cl 2 .
    What tests would you perform to identify the compd? Be specific. Tell what reagents you could use and what observations you could make.
  8. A white amorphous powder A on heating yields a non-combustible gas B and a solid C. The latter compd assumes a yellow color on heating and changes to white on cooling. C dissolves in dil acids and the resultant soln gives a white ppt on adding K[Fe(CN) 4 ] soln. A dissolves in dil HCl with the evolution of a gas which is identical in all respects with B. The gas B turns lime water milky which disappears on continuous passage of it. The soln of A as obtained above gives a white ppt D on addn of excess of NH 4 OH and passing H 2 S. Anther portion of the soln gives initially a white ppt E on addn of NaOH soln which dissolves on further addn of base. Identify A-E.
  9. A colorless solid A on heating gives a white solid B and a gas C; B gives off reddish brown fumes on treatment with dil acids. On heating with NH 4 Cl, B gives a colorless gas D and a residue E. The compd A also gives colorless gas F on heating with ammonium sulphate and white residue G. Both E and G impart yellow color to the Bunsen flame. C forms white powder with strongly heated Mg metal. The white powder forms Mg(OH) 2 with H 2 O. The gas D on the other hand is observed by heated Ca which gives off ammonia on hydrolysis. Identify the substance A to G and give reactions for the changes involved.
  10. A mix of 3 gases A, B, C is passed first into acidified dichromate solution when A is absorbed turning the soln green. The remainder of the gas is passed through excess of lime water which turns milky resulting in the absorption of B. The residual gas C is absorbed by alk pyrogallol soln. However the original mix does not turn lead acetate paper black. Identify A, B, C.