Solved papers for JEE Main & Advanced JEE Main Paper (Held On 12 May 2012)

done JEE Main Paper (Held On 12 May 2012) Total Questions - 30

• question_answer1) The conversion of benzene diazonium chloride to bromobenzene can be accomplished by     JEE Main Online Paper (Held On 12 May 2012)
  A)
  Reimer- Tiemann reacton
  done clear
  B)
  Friedel-Crafts reaction
  done clear
  C)
  Gattermann reaction
  done clear
  D)
  Azo-eoupling reaction
  done clear
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• question_answer2) The radius of a calcium ion is 94 pm and of the oxide ion is 146 pm. The possible crystal structure of calcium oxide will be     JEE Main Online Paper (Held On 12 May 2012)
  A)
  tetrahedral        
  done clear
  B)
                         trigonal
  done clear
  C)
                         octahedral       
  done clear
  D)
                         pyramidal
  done clear
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• question_answer3) The formation of molecular complex \[B{{F}_{3}}-N{{H}_{3}}\]results in a change in hybridization of boron     JEE Main Online Paper (Held On 12 May 2012)
  A)
  from sp2 to dsp2              
  done clear
  B)
                         from sp2 to sp3
  done clear
  C)
                         from sp3 to sp2                 
  done clear
  D)
                         from sp3 to sp3
  done clear
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• question_answer4) A metal Mon heating in nitrogen gas gives Y. Y on treatment with \[{{H}_{2}}O\] gives a colourless gas which when passed through \[CuS{{O}_{4}}\] solution gives a blue colour. V is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[N{{H}_{3}}\]                                  
  done clear
  B)
                         \[Mg{{(N{{O}_{3}})}_{2}}\]
  done clear
  C)
                         \[M{{g}_{3}}{{N}_{2}}\]
  done clear
  D)
                         \[MgO\]
  done clear
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• question_answer5) Water sample is reported to be highly polluted if BOD (Biological Oxygen Demand) value of sample becomes     JEE Main Online Paper (Held On 12 May 2012)
  A)
  more than 17 ppm          
  done clear
  B)
                         equal to 10 ppm
  done clear
  C)
                         equal to 5 ppm                 
  done clear
  D)
                         less than 5 ppm
  done clear
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• question_answer6) A solution containing 0.85 g of \[znC{{l}_{2}}\] in 125.0 g of water freezes at \[-0.23{}^\circ C\]. The apparent degree of dissociation of the salt is (\[{{K}_{f}}\] for water = 1.86 K kg \[\text{mo}{{\text{l}}^{-1}}\], atomic mass: Zn = 65.3 and Cl = 35.5)   JEE Main Online Paper (Held On 12 May 2012)
  A)
  1.36%                                   
  done clear
  B)
  73.5%
  done clear
  C)
  7.35%                                   
  done clear
  D)
  2.47%
  done clear
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• question_answer7) Which of the following complex ions will exhibit optical isomerism? (en = 1,2-diamine ethane).     JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[{{[Cr{{(N{{H}_{3}})}_{2}}C{{l}_{2}}]}^{+}}\]      
  done clear
  B)
                         \[{{[Co{{(en)}_{2}}C{{l}_{2}}]}^{+}}\]
  done clear
  C)
                         \[{{[Co{{(N{{H}_{3}})}_{4}}C{{l}_{2}}]}^{+}}\]     
  done clear
  D)
                         \[{{[Zn{{(en)}_{2}}]}^{2+}}\]
  done clear
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• question_answer8) Which among the following elements has the highest first ionization enthalpy?     JEE Main Online Paper (Held On 12 May 2012)
  A)
  Nitrogen             
  done clear
  B)
                         Boron
  done clear
  C)
                         Carbon                                
  done clear
  D)
                         Oxygen
  done clear
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• question_answer9) Magnetic moment of \[G{{d}^{3+}}ion(Z=64)\]is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  3.62 BM               
  done clear
  B)
                         9.72 BM
  done clear
  C)
                         7.9 BM        
  done clear
  D)
                         10.60 BM
  done clear
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• question_answer10) An aqueous solution of oxalic acid dehydrate contains its 6.3 g in 250 ml. The volume of 0.1N NaOH required to completely neutralize 10 ml of this solution     JEE Main Online Paper (Held On 12 May 2012)
  A)
  4ml                                        
  done clear
  B)
                         20ml
  done clear
  C)
                         2ml                                        
  done clear
  D)
                         40ml
  done clear
  View Answer play_arrow

• question_answer11) In the electrolysis of alumina to obtain aluminium metal, cryolite is added mainly to     JEE Main Online Paper (Held On 12 May 2012)
  A)
  lower the melting point of alumina
  done clear
  B)
                         dissolve alumina in molten cryolite
  done clear
  C)
                         remove the impurities of alumina
  done clear
  D)
                         increase the electrical conductivity
  done clear
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• question_answer12) Synthetic polymer bakelite can be prepared from following compounds     JEE Main Online Paper (Held On 12 May 2012)
  A)
  Styrene and vinyl chloride
  done clear
  B)
                         Acrylonitrile and vinyl chloride
  done clear
  C)
                         Adipic acid and ethylene glycol
  done clear
  D)
                         Phenol and formaldehyde
  done clear
  View Answer play_arrow

• question_answer13) The correct statement for both the processes of physisorption and chemisorption is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  both are endothermic
  done clear
  B)
                         chemisorption is endothermic but physisorption is exothermic
  done clear
  C)
                         both are exothermic
  done clear
  D)
                         physisorption is endothermic but chemisorption is exothermic.
  done clear
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• question_answer14) Which of the following statements is wrong?   JEE Main Online Paper (Held On 12 May 2012)
  A)
  Ethyl chloride on reduction with Zn-Cu couple and alcohol gives ethane.
  done clear
  B)
                         The reaction of methyl magnesium bromide with acetone gives butano1-2.
  done clear
  C)
                         Alkyl halides follow the following reactivity sequence on reaction with alkeries. \[R-I>R-Br>R-Cl>R-I\]
  done clear
  D)
                         \[{{C}_{2}}{{H}_{4}}C{{l}_{2}}\] may exist in two isomeric forms
  done clear
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• question_answer15) Although \[C{{N}^{-}}\]ion and \[{{N}_{2}}\] molecule are isoelectronic, yet \[{{N}_{2}}\] molecule is chemically inert because of     JEE Main Online Paper (Held On 12 May 2012)
  A)
  presence of more number of electrons in bonding orbitals
  done clear
  B)
                         lone bond energy
  done clear
  C)
                         absence of bond polarity
  done clear
  D)
                         uneven electron distribution.
  done clear
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• question_answer16) Amylopectin is a polymer of   JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[\alpha -D-\] glucose   
  done clear
  B)
                         amino acid
  done clear
  C)
                         \[\beta -D-\] glucose     
  done clear
  D)
                         amylase.
  done clear
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• question_answer17) If the radius of first orbit of H atom is \[{{a}_{0}},\] the de- Broglie wavelength of an electron in the third orbit is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[4\pi {{a}_{0}}\]                             
  done clear
  B)
                         \[8\pi {{a}_{0}}\]
  done clear
  C)
                         \[6\pi {{a}_{0}}\]
  done clear
  D)
                         \[2\pi {{a}_{0}}\]
  done clear
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• question_answer18) Chemically heroin is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  morphine monoacetate
  done clear
  B)
                         morphine dibenzbate
  done clear
  C)
                         morphine diacetate  
  done clear
  D)
  morphine monobenzoate
  done clear
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• question_answer19) In the given reaction, the product 'A' is              JEE Main Online Paper (Held On 12 May 2012)
  A)
   
  done clear
  B)
   
  done clear
  C)
   
  done clear
  D)
   
  done clear
  View Answer play_arrow

• question_answer20) The ppm level of \[{{F}^{-}}\]in a 500 g sample of a tooth paste containing 0.2 g \[{{F}^{-}}\]is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  400   
  done clear
  B)
                         1000
  done clear
  C)
                         250                                        
  done clear
  D)
                         200
  done clear
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• question_answer21) In a chemical reaction A is converted into B. The rates of reaction, starting with initial concentrations of A as \[2\times {{10}^{-3}}M\] and \[1\times {{10}^{-3}}M,\]are equal to \[2.40\times {{10}^{-4}}M{{s}^{-1}}\]and \[0.60\times {{10}^{-4}}M{{s}^{-1}}\] respectively. The order of reaction with respect to reactant A will be     JEE Main Online Paper (Held On 12 May 2012)
  A)
  0      
  done clear
  B)
                                1.5
  done clear
  C)
                         1                                             
  done clear
  D)
                         2
  done clear
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• question_answer22) 8 mol of\[A{{B}_{3}}(g)\]are introduced into a 1.0 dm3 vessel. If it dissociates as  \[2A{{B}_{3}}(g){{A}_{2}}(g)+3{{B}_{2}}(g).\]At equilibrium, 2 mol of \[{{A}_{2}}\] are found to be present. The equilibrium constant of this reaction is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  2                                             
  done clear
  B)
                         3
  done clear
  C)
                         27     
  done clear
  D)
                         36
  done clear
  View Answer play_arrow

• question_answer23) 5 g of benzene on nitration gave 6.6 g of nitrobenzene. The theoretical yield of the nitrobenzene will be     JEE Main Online Paper (Held On 12 May 2012)
  A)
  4.5 g                                      
  done clear
  B)
                         5.6g
  done clear
  C)
                         8.09g                                    
  done clear
  D)
                         6.6g
  done clear
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• question_answer24) Given (i)\[HCN(aq)+{{H}_{2}}O(l){{H}_{3}}{{O}^{+}}(aq)+C{{N}^{-}}(aq)\]\[{{K}_{a}}=6.2\times {{10}^{-10}}\] (ii)\[C{{N}^{-}}(aq)+{{H}_{2}}O(l)HCN(aq)+O{{H}^{-}}(aq)\] \[{{K}_{b}}=1.6\times {{10}^{-5}}.\] These equilibria show the following order of the relative base strength,     JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[OH>{{H}_{2}}O>C{{N}^{-}}\]
  done clear
  B)
                         \[O{{H}^{-}}>C{{N}^{-}}>{{H}_{2}}O\]
  done clear
  C)
                         \[{{H}_{2}}O>C{{N}^{-}}>O{{H}^{-}}\]
  done clear
  D)
                         \[C{{N}^{-}}>{{H}_{2}}O>O{{H}^{-}}\]
  done clear
  View Answer play_arrow

• question_answer25) In the below mentioned compounds the decreasing order of reactivity towards electrophilic substitution is (i)??..                                  (ii)                             (iii)                                          (iv)                                   JEE Main Online Paper (Held On 12 May 2012)
  A)
   (iv)>(i)>(ii)>(iii)               
  done clear
  B)
                         (ii)>(iii)>(i)>(iv)
  done clear
  C)
                         (iii)>(i)>(iv)>(ii)
  done clear
  D)
                         (i)>(ii)>(iii)>(iv)
  done clear
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• question_answer26) The difference between the reaction enthalpy change \[({{\Delta }_{r}}H)\]arid reaction internal energy change \[({{\Delta }_{r}}U)\] for the reaction: \[2{{C}_{6}}{{H}_{6}}(l)+15{{O}_{2}}(g)\xrightarrow[{}]{{}}12C{{O}_{2}}(g)+6{{H}_{2}}O(l)\]at 300 K is \[(R=8.314\,J\,mo{{l}^{-1}}\,{{K}^{-1}})\]   JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[0\,J\,mo{{l}^{-1}}\,\]
  done clear
  B)
                         \[2490\,J\,mo{{l}^{-1}}\,\]
  done clear
  C)
                         \[-2490\,J\,mo{{l}^{-1}}\,\]         
  done clear
  D)
                         \[-7482\,J\,mo{{l}^{-1}}\,\]
  done clear
  View Answer play_arrow

• question_answer27) \[C{{H}_{3}}CHO\xrightarrow[Zn\left( Hg \right)/Conc.HCl]{[H]}C{{H}_{3}}C{{H}_{3}}\]The reaction;     JEE Main Online Paper (Held On 12 May 2012)
  A)
  Cannizaro's reaction
  done clear
  B)
                         Rosenmund reduction
  done clear
  C)
                         Wolf-Kishner reduction
  done clear
  D)
                         Clemmenson reduction
  done clear
  View Answer play_arrow

• question_answer28) \[\alpha ,v\]and u represent most probable velocity, average velocity and root mean square velocity respectively of a gas at a particular temperature. The correct order among the following is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[u>v>\alpha \]               
  done clear
  B)
                         \[v>u>\alpha \]
  done clear
  C)
                         \[\alpha >u>v\]               
  done clear
  D)
                         \[u>\alpha >v\]
  done clear
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• question_answer29) Among the following chloro-compound having the lowest dipole moment is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[C{{H}_{3}}Cl\]               
  done clear
  B)
                          
  done clear
  C)
                         \[C{{H}_{2}}C{{l}_{2}}\]
  done clear
  D)
                        
  done clear
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• question_answer30) In the following balanced reaction,\[X\,MnO_{4}^{-}+Y\,{{C}_{2}}O_{4}^{2-}+Z{{H}^{+}}\]\[X\,M{{n}^{2+}}+2Y\,C{{O}_{2}}+\frac{Z}{2}{{H}_{2}}O\]values of X, Y and Z respectively are     JEE Main Online Paper (Held On 12 May 2012)
  A)
  2,5,16   
  done clear
  B)
                         8,2,5
  done clear
  C)
                         5,2,16                                   
  done clear
  D)
                         5,8,4
  done clear
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