Thermodynamics – Important MCQs (NEET 2026)

The standard heat of formation, in kcal/mol of Ba²⁺ is : [Given : standard heat of formation of SO₄²⁻ ion (aq) = −216 kcal/mol, standard heat of crystallisation of BaSO₄(s) = −4.5 kcal/mol, standard heat of formation of BaSO₄(s) = −349 kcal/mol]

The correct thermodynamic conditions for the spontaneous reaction at all temperatures is

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 Gibbs energy change (ΔG) for this transformation will be zero, is

The equilibrium concentrations of the species in the reaction A + B ⇌ C + D are 2, 3, 10 and 6 mol L⁻¹, respectively at 300 K. ΔG⁰ for the reaction is (R = 2 cal/mol K)

For the reaction, X₂O₄(l) → 2XO₂(g), ΔU = 2.1 kcal, ΔS = 20 cal K⁻¹ at 300 K. Hence, G is

The work done during reversible isothermal expansion of one mole of hydrogen gas at 25°C from pressure of 20 atmosphere to 10 atmosphere is (Given R = 2.0 cal K⁻¹ mol⁻¹)

The bond dissociation energies of X₂, Y₂ and XY are in the ratio of 1 : 0.5 : 1. ΔH for the formation of XY is −200 kJ mol⁻¹. The bond dissociation energy of X₂ will be

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

Which one among the following is the correct option for right relationship between C_P and C_V for one mole of ideal gas?

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