The energy required to break one mole of hydrogen-hydrogen bonds

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 Multiple Choice QuestionsMultiple Choice Questions

271.

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

  • 2.84

  • 4.90

  • 1

  • 1

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272.

Which of the following sets of quantum numbers is correct for an electron in 4f orbital?

  • n = 4, I =3, m = +4, s = + 1/ 2

  • n = 3, I = 2, m = -2, S = + 1/2

  • n =4, I = 3, m = +1, s = + 1/ 2

  • n =4, I = 3, m = +1, s = + 1/ 2

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273.

Consider the ground state of Cr atom (Z = 24). The number of electrons with the azimuthal quantum numbers I =1 and 2 are respectively

  • 12 and 4

  • 16 and 5

  • 16 and 4

  • 16 and 4

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274.

The wavelength of the radiation emitted, when in hydrogen atom electron falls from infinity to stationary state 1, would be (Rydberg constant = 1.097×107 m-1)

  • 91 nm

  • 9.1×10-8 nm

  • 406 nm

  • 406 nm

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275.

If the given four electronic configurations,

(i) n = 4, l = 1

(ii) n = 4, l = 0

(iii) n = 3, l = 2

(iv) n = 3, l = 1

are arranged in order of increasing energy, then the order will be

  • (iv) < (ii) < (iii) < (i)

  • (ii) < (iv) < (i) < (iii)

  • (i) < (iii) < (ii) < (iv)

  • (iii) < (i) < (iv) < (ii)


276.

Which of the following sets of quantum numbers represents the 19th electron of Cr(Z = 24)?

  • (4, 1, -1, +12)

  • (4, 0, 0, +12)

  • (3, 2, 0, -12)

  • (3, 2, -2, +12)


277.

C6H5F18 is a F18  radio-isotope labelled organic compound. F18 decays by positron emission. The product resulting on decay is 

  • C6H5O18

  • C6H5Ar19

  • B12C5H5F

  • C6H5O16


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278.

The energy required to break one mole of hydrogen-hydrogen bonds in H2 is 436 kJ. What is the longest wavelength of light required to break a single hydrogen-hydrogen bond?

  • 68.5nm

  • 137nm

  • 274nm

  • 584nm


C.

274nm

 Given, energy of one mole of H, bonds = 436 KJ                 E=n·hcλ              (energy for oneH-H bond)                 λ= n·hcE              (n=number of H-H bonds)    λ= 6.634 x 10-34Js ×3×108ms-1×6.023×1023436×103 Jm       = 0.2736 × 10- 34+ 8+ 23 - 3       = 0.2736  × 10-6 m       = 273.6 nm= 274 nm


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279.

An element E loses one α and two β particles in three successive stages. The resulting elemenl wiil be

  • an isobar of E

  • an isotone of E

  • an isotope of E

  • E itself


280.

Which one of the following corresponds to a photon of highest energy?

  • λ = 300 mm

  • v = 3 × 108 s-1

  • v = 30 cm-1

  • ε = 6.626 × 10-27 J


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