Thermodynamics: NEET questions with solutions

NEET tests the first law sign convention, ΔH–ΔU conversion, Hess's law and bond-enthalpy arithmetic, reversible work, and ΔG = ΔH − TΔS spontaneity logic. Most lost marks come from sign errors (work done by vs on the system), kJ–J mismatches, counting liquid water as gas in Δng, and forgetting stoichiometric coefficients in Hess's law.

1. 1.Which set contains ONLY state functions?Internal energy as a state functionEasySingle correct
2. 2.A gas in a cylinder absorbs 250 J of heat from the surroundings and, in the same process, does 400 J of work on the surroundings by…First law of thermodynamicsEasySingle correct
3. 3.In a bomb calorimeter at 298 K, the internal energy change for the complete combustion of liquid ethanol is ΔU = −1364.5 kJ mol⁻¹:Enthalpy: relation between ΔH and ΔUMediumSingle correct
4. 4.Use the following data at 298 K to find the standard enthalpy of formation of propane, C₃H₈(g):Hess's law of constant heat summationMediumSingle correct
5. 5.A reaction has ΔH > 0 and ΔS > 0, and both are nearly independent of temperature. Under what conditions is the reaction spontaneous at…Gibbs energy and spontaneityEasySingle correct
6. 6.A solid decomposes with ΔH° = +178.0 kJ mol⁻¹ and ΔS° = +160.0 J K⁻¹ mol⁻¹. Assuming both are independent of temperature, in which…Gibbs energy: threshold temperatureMediumSingle correct
7. 7.2.0 mol of an ideal gas expands isothermally and reversibly at 300 K from 10.0 L to 100.0 L. What is the work done on the gas?Work: isothermal reversible expansion of an ideal gasMediumSingle correct
8. 8.Consider the following statements and choose the option that lists ALL the correct ones.Thermodynamic terms and enthalpyHardStatement based
9. 9.Using the mean bond enthalpies below, estimate ΔrH for the gas-phase hydrogenation of ethene:Bond enthalpyHardSingle correct