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

2007 · Q91
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. /2007 · Q91

Thermodynamics question

2007 · Q91

NEETChemistryThermodynamicsMCQ+4 / −1
Consider the following reactions :
(i) H+(aq) + OH−-−(aq) = H2O(l),  Δ\DeltaΔH = −-− X1 kJ mol−-−1
(ii) H2(g) + 1/2O2(g) = H2O(l),   Δ\DeltaΔH = −-− X2 kJ mol−-−1
(iii) CO2(g) + H2(g) = CO(g) + H2O(l),  Δ\DeltaΔH = −-− X3 kJ mol−-−1
(iv) C2H2(g) + 5/2O2(g) = 2CO2(g) + H2O(l),    Δ\DeltaΔH = +X4 kJ mol−-−1

Enthalpy of formation of H2O(l) is
  1. A
    +X3 kJ mol−-−1
  2. B
    −-−X4 kJ mol−-−1
  3. C
    +X1 kJ mol−-−1
  4. D
    −-−X2 kJ mol−-−1
View written solutionFree

Correct answer: D

Chemical equation for the formation of H2O(l) is

H2(g) + 1/2O2(g) = H2O(l)

Because enthalpy of formation of a compound is the heat absorbed or released when one mole of this substance is formed from its constituent elements.

Thus, enthalpy of formation of H2O is –X2 kJ mol–1 where negative sign shows that the reaction is exothermic.

Equation (i) represents nutralisation reaction.

Equation (iii) represents hydrogenation reaction.

Equation (iv) represents combustion reaction.

PreviousNext

More from Thermodynamics

  • Given that bond energies of H − H and Cl − Cl are 430 kJ mol−1 and 240 kJ mol−1 respectively and ΔHf for HCl is − 90 kJ mol−1, bond enthalpy of HCl is2007 · MCQ
  • Identify the correct statement for change of Gibb's energy for a system (ΔGsystem) at constant temperature and pressure.2006 · MCQ
  • The enthalpy and entropy change for the reaction: Br2(l) + Cl2(g) → 2BrCl(g) are 30 kJ mol−1 and 105 J K−1 mol−1 respectively. The temperature at which the reaction will be in equilibrium is2006 · MCQ
  • The enthalpy of hydrogenation of cyclohexene is is − 119.5 kJ mol−1. If resonance energy of benzene is − 150.4 kJ mol−1, its enthalpy of hydrogenation would be2006 · MCQ
  • Assume each reaction is carried out in an open container. For which reaction will ΔH = ΔE ?2006 · MCQ
  • Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction ?2005 · MCQ
  • A reaction occurs spontaneously if2005 · MCQ
  • The absolute enthalpy of neutralisation of the reaction : Mg(O)(s) + 2HCl(aq) → MgCl2(aq) + H2O(l) will be2005 · MCQ