sign up I login
 advanced
refer a friend - earn nickels!!

Community Contributions - Articles by goIITians

  Back to Community Shelf like the article? email it to a friend. email this article!  
  please comment   Awaiting Review for Nickels
Tagged with:  academic    [Post New]posted on 19 Apr 2008 19:26:36 IST    

Chemistry

hey guys i have kept some question in chemistry try to solve them i will keep key after half an hour 

SECTION ? A

@    Write-up I [Questions 1 to 4]
            Three elements X, Y and Z, are in the same period of the periodic table. The accompanying table gives some data concerning the elements and their oxides. One of the elements forms another oxide in addition to that listed.
Element
X
Y
Z
Appearnace Oxide
Shiny black solid white solid, XO2
Silvery solid white solid, YO
Yellow crystals white solid, ZO3
            Use the letters, X, Y and Z in answering the following questions. Do not try to identify the elements.
1.         Write the letters X, Y and Z in the order in which the elements appear in the period
            (a)  Y, X, Z                                                      (b)  Y, Z, X
            (c)  X, Y, Z                                                      (d) Z, X, Y
2.         To which groups do the elemnets belong?
            (a)  X is in group II, Y is in group IV, Z is in group VI
            (b)  Z is in group II, X is in group IV, Y is in group VI
            (c)  X is in group II, Z is in group IV, Y is in group VI
            (d) Y is in group II, X is in group IV, Z is in group VI
3.         Where the formulae of the compounds which the elements would form with hdyrogen
            (a)  YH2, XH4, ZH6                                         (b)  YH2, XH4, ZH2
            (c)  Y2H, XH4, ZH4                                         (d) YH2, XH2, ZH6
 
4.         Which element would be the best conductor of electricity?
            (a)  Y                                                               (b)  X
            (c)  Z                                                                (d) None
@       Write-up II [Questions 5 to 8]
            The diagrams below show the structures of some common elements or compounds
            A
B
            C
D
            E
 
 
5.         Which structure shows the arrangement of atoms in a diamond?
            (a)  E                                                                (b)  A
            (c)  C                                                               (d) D
6          Which structure shows the arrangement of ions in a crystal of sodium chloride
            (a)  C                                                               (b)  B
            (c)  D                                                               (d) E   
7.         The structure of SO2 will be
            (a)  B                                                               (b)  D
            (c)  A                                                               (d) C
8.         The structure  will be
            (a)  D                                                               (b)  B
            (c)  A                                                               (d) C
@       Write-up III [Questions 9 to 12]
            CaC2 is the starting material for large scale production of a number of valuable organic compounds on the cheapest possible way. CaC2 is first treated with water to evolve a gas which upon acid catalysed hydration gives an organic compound (A). A upon oxidation and subsequent dry distillation of the Ca salt of the oxidised product gives a compound (B).
9.         The compound (A) and (B) can be distinguished by
            (a)  Iodoform test                                           
            (b)  NaHSO3 addition test
            (c)  Tollen?s reagent test                                 
            (d) 2,4 DNP condensation test
10.       The gas upon treatment with calculated amount of NaNH2 (1 : 1 molar proportion) and subsequent treatment with ethyl iodide gives a compound that upon HBO gives a compound (C). The compound (C) is
            (a)  Butanal                                                      (b)  Butanone
            (c)  2-Butanol                                                  (d) 1-Butanol
11.       The compound before being subjected to HBO, on being subjected once again to the same treatment as in 2 given above, gives a compound which is further subjected to hydrogenation with sodium in liquid NH3 to give a compound (D). Hence (D) is
            (a)  cis-hex-3-ene                                             (b)  trans-hex-3-ene
            (c)  n-hexane                                                    (d) hex-3-yne
12.       The treatment of (D) with Br2/CCl4 gives an organic compound (E). Hence E is
            (a)
(b)
            (c)
(d)
@       Write-up IV [Questions 13 to 16]
            From the following list of substances: copper (II) chloride, hydrogen chloride, copper, potassium chloride and iodine, name those that:
13.       Conduct electricity in the soild state
            (a)  Copper                                                      (b)  copper chloride
            (c)  hydrogen chloride                                     (d) potassium chloride
14.       Conduct electricity when molten
            (a)  Copper (II) chloride, copper, potassium chloride
            (b)  Copper (II) chloride, potassium chloride
            (c)  Copper, potassium chloride
            (d) Copper (II) chloride, copper
15.       Conduct electricity in aqueous solution
            (a)  Copper (II) chloride, hydrogen chloride, potasisum chloride
            (b)  Copper (II) chloride, potasisum chloride
            (c)  Copper (II) chloride, hydrogen chloride, copper
            (d) Copper (II) chloride, hydrogen chloride, potasisum chloride, copper
16.       Do not readily conduct under any conditions
            (a)  Copper                                                      (b)  Iodine
            (c)  hydrogen chloride                                     (d) Copper chloride
@       Write-up V [Questions 17 to 20]
            The colours of some indicators in solutions at varous pH values are shown in the table below:
Indicator
pH
2
3
4
5
6
7
8
9
10
11
Methyl yellow
R
 
Y
 
 
 
 
 
 
 
Litmus
 
 
 
 
R
 
B
 
 
 
Bromothymol blue
 
 
 
 
Y
G
B
 
 
 
Phenolphthalein
 
 
 
 
 
 
C
 
R
 
            Key: B = Blue, G = Green, Y = Gellow, C = colourless, R = red
 
17.       Predict the colour shown by litmus in a solution of pH 7
            (a)  Blue                                                           (b)  Red
            (c)  Purple                                                        (d) Colourless
18.       A solution of ethanoic aid has pH 5. What colour would be shown by the methyl yellow indicators in the acid solution?
            (a)  Green                                                        (b)  Red
            (c)  Oragne                                                      (d) Yellow
19.       In the titration of H3PO4 with NaOH the suitable indicator for first equivalence point is
            (a)  Methyl yellow                                           (b)  Litmus
            (c)  Phenolphthalein                                        (d) None
20.       A solution of sodium carbonate turns litmus blue and phenolphthalein red. Suggest the pH value of this solution.
            (a)  7                                                                (b)  9
            (c)  10                                                              (d) 4
@       Write-up VI Questions 21 to 24]