JEE Advance - Chemistry (1982)

• 1

  The energy released when an electron is added to a neutral gaseous atom is called ______ of the atom.

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  (C)

  Electron affinity
• 2

  The oxidation number of carbon in CH₂O is

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  (C)

  0
• 3

  Hydroxylamine reduces iron (III) according to the equation:
  
  2NH₂OH + 4Fe³⁺ $$\to$$ N₂O(g) $$ \uparrow $$ + H₂O + 4Fe²⁺ + 4H⁺
  
  Iron (II) thus produced is estimated by titration with a standard permanganate solution. The reaction is :
  
  $$MnO_4^-$$ + 5Fe²⁺ + 8H⁺ $$\to$$ Mn²⁺ + 5Fe³⁺ + 4H₂O
  
  A 10 ml sample of hydroxylamine solution was Diluted to 1 litre. 50 ml of this diluted solution was boiled with an excess of iron (III) solution. The resulting solution required 12 ml of 0.02 M KMnO₄ solution for complete oxidation of iron (II). Calculate the weight of hydroxylamine in one litre of the original solution. (H = 1, N = 14, O = 16, K =39, Mn = 55, Fe = 56)

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  (D)

  39.6 g/l
• 4

  The mass of a hydrogen atom is ______ kg.

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  (B)

  1.673 × 10^-27
• 5

  Isotopes of an element differ in the number of ______ in their nuclei.

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  (C)

  neutrons
• 6

  When there are two electrons in the same orbital, they have _____ spins.

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  (B)

  antiparallel
• 7

  The outer electronic configuration of the ground state chromium atom is 3d⁴ 4s²

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  (B)

  FALSE
• 8

  Calculate the wavelength in Angstrom of the photon that is emitted when an electron in the Bohr orbit, n = 2 returns to the orbit, n = 1 in the hydrogen atom. The ionization potential of the ground state hydrogen atom is 2.17 $$\times$$ 10^-11 erg per atom.

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  (C)

  1216 Å
• 9

  The element with the highest first ionization potential is

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  (C)

  nitrogen
• 10

  There are ______ $$\pi$$ bonds in a nitrogen molecule.

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  2
• 11

  ____ hybrid orbitals of nitrogen atom are involved in the formation of ammonium ion.

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  (C)

  sp³
• 12

  The ion that is isoelectronic with CO is

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  (A)

  CN^-
• 13

  Among the following, the molecule that is linear is

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  (A)

  CO₂
• 14

  The compound with no dipole moment is

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  (B)

  carbon tetrachloride
• 15

  Helium atom is two times heavier than a hydrogen molecule. At 298 K, the average kinetic energy of a helium atom is

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  (C)

  same as that of a hydrogen molecule
• 16

  At room temparature, ammonia gas at 1 atm pressure and hydrogen chloride gas at P atm pressure are allowed to effuse through identical pin holes from opposite ends of a glass tube of one metre length and of uniform cross-section. Ammonium chloride is first formed at a distance of 60 cm from the end through which HCL gas is sent in. What is the value of P?

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  (C)

  4.83 atm
• 17

  MgCl₂.6H₂O on heating give anhydrous MgCl₂

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  (B)

  FALSE
• 18

  How will you prepare bleaching powder from slaked lime.

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  (A)

  By treating slaked lime with chlorine gas.
• 19

  Write down the balanced equations for the reaction when:
  An alkaline solution of potassium ferricyanide is reacted with hydrogen peroxide.

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  (A)

  2K3[Fe(CN)6] + H2O2 + 2KOH -> 2K4[Fe(CN)6] + 2H2O + O2