JEE Advance - Chemistry (1984)

• 1

  When alpha particles are sent through a thin metal foil, most of them go straight through the foil because

  Vastaus

  A

  C
• 2

  The electron energy in hydrogen atom is given by E = (-21.7 $$\times$$ 10^-12)/n² ergs. Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength (in cm) of light that can be used to cause this transition?

  Vastaus

  (A)

  5.42 x 10^-12 ergs, 3.66 x 10^-5 cm
• 3

  On hybridization of one s and one p orbitals we get:

  Vastaus

  (B)

  two orbitals at 180^o
• 4

  The total energy of one mole of an ideal monatomic gas at 27^o is _______ calories.

  Vastaus

  900
• 5

  Which electronic level would allow the hydrogen atom to absorb a photon but not to emit a photon?

  Vastaus

  (D)

  1s
• 6

  An isotone of $${}_{32}^{76}Ge$$ is

  Vastaus

  B

  D
• 7

  When alpha particles are sent through a thin metal foil, most of them go straight through the foil because

  Vastaus

  A

  C
• 8

  The electron energy in hydrogen atom is given by E = (-21.7 $$\times$$ 10^-12)/n² ergs. Calculate the energy required to remove an electron completely from the n = 2 orbit. What is the longest wavelength (in cm) of light that can be used to cause this transition?

  Vastaus

  (A)

  5.42 \(\times\) 10^-12 ergs, 3.67 \(\times\) 10^-5 cm
• 9

  On hybridization of one s and one p orbitals we get:

  Vastaus

  (B)

  two orbitals at 180^o
• 10

  The total energy of one mole of an ideal monatomic gas at 27^o is _______ calories.

  Vastaus

  900
• 11

  C_p - C_v for an ideal gas is _______

  Vastaus

  (B)

  R
• 12

  Equal weights of methane and hydrogen are mixed in an empty container at 25^oC. The fraction of the total pressure exerted by hydrogen is

  Vastaus

  (B)

  8/9
• 13

  The hydration energy of Mg⁺⁺ is larger than that of:

  Vastaus

  (B)

  Na⁺
• 14

  The IUPAC name of the compound having the formula is :

  Vastaus

  (C)

  3, 3-dimethylbut-1-ene
• 15

  When 16.8 g of white solid X were heated, 4.4 g of acid gas A, that turned lime water milky was driven off together with 1.8 g of a gas B which condensed to a colourless liquid.

  The solid that remained, Y, dissolved in water to give an alkaline solution, which with excess barium chloride solution gave a white precipitate Z. The precipitate efferversced with acid giving off carbon dioxide. Identify A, B and Y and write down the equation for the thermal decomposition of X.

  Vastaus

  (A)

  A is CO2, B is H2O, Y is Na2CO3, X is NaHCO3, Decomposition Equation: 2NaHCO3(s) → Na2CO3(s) + H2O(g) + CO2(g)