JEE MAIN - Chemistry (2006)

• 1

  The standard enthalpy of formation $$\Delta _fH^o$$ at 298 K for methane, CH₄(g), is –74.8 kJ mol^–1. The additional information required to determine the average energy for C – H bond formation would be :

  回答

  (A)

  the dissociation energy of H₂ and enthalpy of sublimation of carbon
• 2

  An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If T_i is the initial temperature and T_f is the final temperature, which of the following statements is correct?

  回答

  (A)

  (T_f)_irrev > (T_f)_rev
• 3

  The enthalpy changes for the following processes are listed below :
  
  Cl₂(g) = 2Cl(g), 242.3 kJ mol^–1
  I₂(g) = 2I(g), 151.0 kJ mol^–1
  ICl(g) = I(g) + Cl(g), 211.3 kJ mol^–1
  I₂(s) = I₂(g), 62.76 kJ mol^–1
  
  Given that the standard states for iodine and chlorine are I₂(s) and Cl₂(g), the standard enthalpy of formation for ICl(g) is :

  回答

  (C)

  +16.8 kJ mol^–1
• 4

  ($$\Delta H - \Delta U$$) for the formation of carbon monoxide (CO) from its elements at 298 K is : (R = 8.314 J K^–1 mol^–1)

  回答

  (B)

  1238.78 J mol^–1
• 5

  Phosphorus pentachloride dissociates as follows, in a closed reaction vessel
  PCl₅ (g) $$\leftrightharpoons$$ PCl₃ (g) + Cl₂ (g)
  If total pressure at equilibrium of the reaction mixture is P and degree of dissociation of PCl₅ is x, the partial pressure of PCl₃ will be

  回答

  (A)

  $$\left( {{x \over {x + 1}}} \right)P$$
• 6

  The equilibrium constant for the reaction
  SO₃ (g) $$\leftrightharpoons$$ SO₂ (g) + $$1 \over 2$$ O₂ (g)
  is K_c = 4.9 $$\times$$ 10^–2. The value of K_c for the reaction
  2SO₂ (g) + O₂ (g) $$\leftrightharpoons$$ 2SO₃ (g) will be :

  回答

  (A)

  416
• 7

  Given the data at 25^oC,
  Ag + I^- $$\to$$ AgI + e^- , E^o = 0.152 V
  Ag $$\to$$ Ag⁺ + e^-, E^o = -0.800 V
  What is the value of log K_sp for AgI? (2.303 RT/F = 0.059 V)

  回答

  (D)

  –16.13
• 8

  CH₃Br + Nu^- $$\to$$ CH₃ - Nu + Br^- The decreasing order of the rate of the above reaction with nucleophiles (Nu^–) A to D is
  [Nu^– = (A) PhO^–, (B) AcO^–, (C) HO–, (D) CH₃O^–]

  回答

  (C)

  D > C > A > B
• 9

  The increasing order of stability of the following free radicals is

  回答

  (B)

  $${(C{H_3})_2}\mathop C\limits^ \bullet H$$ < $${(C{H_3})_3}\mathop C\limits^ \bullet $$ < $${({C_6}{H_5})_2}\mathop C\limits^ \bullet H$$ < $${({C_6}{H_5})_3}\mathop C\limits^ \bullet$$
• 10

  Increasing order of stability among the three main conformations (i.e. Eclipse, Anti, Gauche) of 2-fluoroethanol is

  回答

  (C)

  Eclipse, Anti, Gauche
• 11

  CH₃Br + Nu^- $$\to$$ CH₃ - Nu + Br^- The decreasing order of the rate of the above reaction with nucleophiles (Nu^–) A to D is
  [Nu^– = (A) PhO^–, (B) AcO^–, (C) HO–, (D) CH₃O^–]

  回答

  (C)

  D > C > A > B
• 12

  How many EDTA (ethylenediaminetetraacetic acid) molecules are required to make an octahedral complex with a Ca²⁺ ion?

  回答

  (C)

  One
• 13

  Phenyl magnesium bromide reacts with methanol to give

  回答

  (B)

  a mixture of benzene and Mg(OMe)Br
• 14

  Fluorobenzene (C₆H₅F) can be synthesized in the laboratory

  回答

  (B)

  from aniline by diazotisation followed by heating the diazonium salt with HBF₄
• 15

  Reaction of trans-2-phenyl-1-bromocyclopentane on reaction with alcoholic KOH produces

  回答

  (D)

  3-phenylcyclopentene
• 16

  HBr reacts with CH₂ = CH – OCH₃ under anhydrous conditions at room temperature to give

  回答

  (D)

  H₃C – CHBr – OCH₃
• 17

  The term anomers of glucose refers to

  回答

  (D)

  isomers of glucose that differ in configuration at carbon one (C-1)
• 18

  The pyrimidine bases present in DNA are

  回答

  (C)

  cytosine and thymine
• 19

  In Fe(CO)₅, the Fe – C bond possesses :

  回答

  (B)

  both $$\sigma$$ and π characters
• 20

  The $$IUPAC$$ name of the compound shown below is :
  
  

  回答

  (A)

  $$3$$-bromo - $$1$$-chlorocyclohexene
• 21

  
  
  The alkene formed as a major product in the above elimination reaction is

  回答

  (B)

  
• 22

  The structure of the major product formed in the following reaction
  
  
  is

  回答

  (B)

  
• 23

  The structure of the compound that gives a tribromo derivative on treatment with bromine water is

  回答

  (C)

  
• 24

  
  
  The electrophile involved in the above reaction is

  回答

  (D)

  
• 25

  Among the following the one that gives positives iodoform test upon reaction with $${I_2}$$ and $$NaOH$$ is

  回答

  (B)

  $$PhCHOHC{H_3}$$
• 26

  The correct order of increasing acid strength of the compounds
  
  

  回答

  (A)

  $$D < A < B < C$$
• 27

  A metal, $$M$$ forms chlorides in its $$+2$$ and $$+4$$ oxidation states. Which of the following statements about these chlorides is correct?

  回答

  (A)

  $$MC{l_2}$$ is more ionic than $$MC{l_4}$$
• 28

  Rate of a reaction can be expressed by Arrhenius equation as:
  $$$k = A\,{e^{ - E/RT}}$$$ In this equation, E represents

  回答

  (A)

  the energy above which all the colliding molecules will react
• 29

  Among the following mixtures, dipole-dipole as the major interaction, is present in

  回答

  (B)

  acetonitrile and acetone
• 30

  18 g of glucose (C₆H₁₂O₆) is added to 178.2 g of water. The vapour pressure of water for this aqueous solution at 100^oC is

  回答

  (D)

  752.40 Torr
• 31

  The molar conductivities $$ \wedge _{NaOAc}^o$$ and $$ \wedge _{HCl}^o$$ and at infinite dilution in water at 25^oC are 91.0 and 426.2 Scm²/mol respectively. To calculate $$ \wedge _{HOAc}^o$$ , the additional value required is

  回答

  (D)

  $$ \wedge _{NaCl}^o$$
• 32

  Which of the following chemical reactions depicts the oxidizing behaviour of H₂SO₄?

  回答

  (C)

  2HI + H₂SO₄ $$\to$$ I₂ + SO₂ + 2H₂O
• 33

  Resistance of a conductivity cell filled with a solution of an electrolyte of concentration 0.1 M is 100$$\Omega $$. The conductivity of this solution is 1.29 S m^–1. Resistance of the same cell when filled with 0.2 M of the same solution is 520 $$\Omega $$, The molar conductivity of 0.02 M solution of the electrolyte will be

  回答

  (D)

  12.4 $$\times$$ 10^–4 S m² mol^–1
• 34

  A reaction was found to be second order with respect to the concentration of carbon monoxide. If the concentration of carbon monoxide is doubled, with everything else kept the same, the rate of reaction will

  回答

  (C)

  increase by a factor of 4
• 35

  In the transformation of $${}_{92}^{238}U$$ to $${}_{92}^{234}U$$, if one emission is an α-particle, what should be the other emission(s)?

  回答

  (A)

  Two $$\beta^-$$
• 36

  The following mechanism has been proposed for the reaction of NO with Br₂ to form NOBr:
  NO(g) + Br₂ (g) $$\leftrightharpoons$$ NOBr₂ (g)
  NOBr₂ (g) + NO (g) $$\to$$ 2NOBr (g)
  If the second step is the rate determining step, the order of the reaction with respect to NO(g) is

  回答

  (D)

  2
• 37

  The increasing order of the first ionization enthalpies of the elements B, P, S and F (lowest first) is :

  回答

  (D)

  B < S < P < F
• 38

  Which of the following statements is true?

  回答

  (D)

  HNO₃ is a stronger acid than HNO₂
• 39

  The “spin-only” magnetic moment [in units of Bohr magneton, (µ_B)] of Ni²⁺ in aqueous solution would be : (Atomic number of Ni = 28)

  回答

  (A)

  2.84
• 40

  Lanthanoid contraction is caused due to :

  回答

  (D)

  the imperfect shielding on outer electrons by 4f electrons from the nuclear charge
• 41

  Nickel (Z = 28) combines with a uninegative monodentate ligand X^– to form a paramagnetic complex [NiX₄]²⁻ . The number of unpaired electron(s) in the nickel and geometry of this complex ion are, respectively

  回答

  (B)

  two, tetrahedral
• 42

  How many moles of magnesium phosphate Mg₃(PO₄)₂ will contain 0.25 mole of oxygen atoms?

  回答

  (D)

  3.125 $$\times$$ 10^-2
• 43

  Density of a 2.05M solution of acetic acid in water is 1.02 g/mL The molality of the solution is

  回答

  (A)

  2.28 mol kg^-1
• 44

  Uncertainty in the position of an electron (mass = 9.1 $$\times$$ 10^-31 kg) moving with a velocity 300 ms^-1, accurate upto 0.001% will be (h = 6.63 $$\times$$ 10^-34 Js)

  回答

  (A)

  1.92 $$\times$$ 10^-2 m
• 45

  Uncertainty in the position of an electron (mass = 9.1 $$\times$$ 10^-31 kg) moving with a velocity 300 ms^-1, accurate upto 0.001% will be (h = 6.63 $$\times$$ 10^-34 Js)

  回答

  (A)

  1.92 $$\times$$ 10^-2 m
• 46

  According to Bohr's theory, the angular momentum of an electron in 5^th orbit is

  回答

  (B)

  2.5 $$h/\pi$$
• 47

  Which of the following sets of ions represents a collection of isoelectronic species?

  回答

  (C)

  K⁺, Cl^-, Ca²⁺, Sc³⁺
• 48

  Following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statements gives the correct picture?

  回答

  (D)

  In alkali metals the reactivity increases but in the halogens it decreases with increase in atomic number down the group
• 49

  Which of the following molecules/ions does not contain unpaired electrons?

  回答

  (A)

  $$O_2^{2−} $$
• 50

  In which of the following molecules/ions are all the bonds not equal?

  回答

  (C)

  SF₄
• 51

  The decreasing values of bond angles from NH₃ (106^o) to SbH₃ (91^o ) down group-15 of the periodic table is due to

  回答

  (C)

  decreasing lp-bp repulsion