Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Thermodynamics question

2012 · Q117
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /NEET
  3. /Chemistry
  4. /Thermodynamics
  5. /2012 · Q117

Thermodynamics question

2012 · Q117

NEETChemistryThermodynamicsMCQ+4 / −1
In which of the following reactions, standard reaction entropy change (Δ\DeltaΔSo) is positive and standard Gibb's energy change (Δ\DeltaΔGo) decreases sharply with increasing temperature ?
  1. A
    C(graphite) + 12{1 \over 2}21​O2(g) →\to→ CO(g)
  2. B
    CO(g) + 12{1 \over 2}21​O2(g) →\to→ CO2(g)
  3. C
    Mg(s) + 12{1 \over 2}21​O2(g) →\to→ MgO(g)
  4. D
    12{1 \over 2}21​C(graphite) + 12{1 \over 2}21​O2(g) →\to→ 12{1 \over 2}21​CO2(g)
View written solutionFree

Correct answer: A

Δ\Delta ΔSo positive means entropy of products is more than that of reactants. Among the given reactions only in option (a) the Δ\Delta ΔSo is positive cause products has 1 mole of gaseous products CO while reaction have half mole of gaseous O2 and Carbon (C) in solid state. Thus, reactions have less randomness than products. Also, the reaction is a combustion reaction which has a negative value of Δ\Delta ΔH. According to Gibbs energy change (Δ\Delta ΔSo).

Δ\Delta ΔGo = Δ\Delta ΔHo - TΔ\Delta ΔSo

⇒\Rightarrow⇒ Δ\Delta ΔGo = -ve - T(+ve)

Thus, on increasing temperature value of Δ\Delta ΔGo decreases sharply.

PreviousNext

More from Thermodynamics

  • Standard enthalpy of vaporisation ΔvapHo for water at 100oC is 40.66 kJ mol−1. The internal energy of vaporisation of water at 100oC (in kJ mol−1) is2012 · MCQ
  • The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0oC is2012 · MCQ
  • Consider the following processes : For B + D → E + 2C, ΔH will be Includes table2011 · MCQ
  • If the enthalpy change for the transition of liquid water to steam is 30 kJ mol−1 at 27oC, the entropy change for the process would be2011 · MCQ
  • Enthalpy change for the reaction, 4H(g) → 2H2(g) is −869.6 kJ The dissociation energy of H − H bond is2011 · MCQ
  • Which of the following is correct option for free expansion of an ideal gas under adiabatic condition ?2011 · MCQ
  • The following two reactions are known Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g); ΔH = − 26.8 kJ FeO(s) + CO(g) → Fe(s) + CO2(g); ΔH = − 16.5 kJ The value of ΔH for the following reaction Fe2O3(s) + CO(g) →…2010 · MCQ
  • For vaporization of water at 1 atmospheric pressure, the values of ΔH and ΔS are 40.63 kJ mol−1 and 108.8 J K−1 mol−1, respectively. The temperature when Gibb's energy change (ΔG) for this transformation will…2010 · MCQ