Enthalpy change for the reaction,4H (g) → 2H2 (g) is - 869.6

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 Multiple Choice QuestionsMultiple Choice Questions

261.

Which of the following statements is correct for a reversible process in a state of equilibrium?

  • ΔG = -2.303RT log K
  • ΔG = 2.303RT log K

  • ΔG0 = -2.303RT log K

  • ΔG0 = -2.303RT log K

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262.

Which of the following statement is correct for the spontaneous absorption of a gas?

  • ΔS is negative and therefore, ΔH should be highly positive
  • ΔS is negative and therefore, ΔH should be highly negative
  • ΔS is positive and therefore, ΔH should be negative
  • ΔS is positive and therefore, ΔH should be negative
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263.

For the reaction X2O4 (l) -->  2XO2 (g) ΔU = 2.1 kcal, ΔS = 20 cal K-1 at 300 K hence ΔG is

  • 2.7 kcal

  • -2.7kcal

  • 9.3 kcal 

  • 9.3 kcal 

4144 Views

264.

A reaction having equal energies of activation for forward and reverse reactions has

  • ΔS =0
  • ΔG =0
  • ΔH = 0
  • ΔH = 0
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265.

In which of the following reactions, standard reaction entropy changes (ΔSo) is positive and standard Gibb's energy change (ΔGo) decreases sharply with increasing temperature?

  • C (graphite) +1/2 O2 (g) → CO (g)

  • CO (g) +1/2 (g) → CO2 (g)

  • Mg(s)  +1/2O2 (g) → MgO (s)

  • Mg(s)  +1/2O2 (g) → MgO (s)

1457 Views

266.

The enthalpy of fusion of water is 1.435 Kcal/mol. The molar entropy change for the melting of ice of at 0o C is

  • 10.52 cal/(mol K)

  • 21.04 cal/(mol K)

  • 5.260 cal/ (mol K)

  • 5.260 cal/ (mol K)

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267.

Standard enthalpy of vaporisation ΔvapHθ for water for water at 100oC is 40.66 kJ mol-1. The internal energy of vaporisation of water at 100o C (in KJ mol-1) is

(Assume water vapour to behave like an ideal gas.)

  • +37.56

  • -43.76

  • +43.76

  • +43.76

594 Views

268.

If the enthalpy change for the transition of liquid water to steam is 30kJ mol-1 at 27oC, the entropy change for the process would be. 

  • 1.0 J mol- K-1

  • 0.1 J mol-1 K-1

  • 100 J  mol-1 K-1

  • 10 J mol-1 K-1

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269.

Which of the following is the correct option for free expansion of an ideal gas under an adiabatic condition?

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270.

Enthalpy change for the reaction,

4H (g) → 2H2 (g) is - 869.6 kJ

The dissociation energy of H - H bond is

  • -869.6 kJ

  • +434.8 kJ

  • +217.4 kJ

  • +217.4 kJ


B.

+434.8 kJ

4H (g) → 2H2 (g); ΔH = - 869.6 kJ

2H2 (g) → 4 H (g); ΔH =  869.6 kJ

H2 (g) → 2 H (g); ΔH = 869.6/2 = 434.8 kJ

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