Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEETChemistryThermodynamics (C)

Which of the following reactions does not involve absorption of energy? I. O g + e - ⟶ O - g II. S g + e - ⟶ S - g III. O - g + e - ⟶ O 2 - g IV. Cl g + e - ⟶ Cl - g

Options

  1. AOnly II
  2. BI and III
  3. CI ,   II and III
  4. DI ,   II and IV

Correct answer

D. I ,   II and IV

Step-by-step solution

Reaction ( I ) , ( II ) and ( IV ) are of exothermic nature, thus do not involve absorption energy. The process O - g + e - ⟶ O 2 - g ​ involves absorption of energy. When a neutral atom gains an electron, energy is released. When an anion (having unit negative charge) gains an electron, energy is absorbed. This is due to the repulsion between the additional electron and negatively charged anion.

Practice Thermodynamics (C) on Quantrex Academy →

More from Thermodynamics (C)

A certain organic solvent has H _vap = 28.50 kJ mol ⁻¹ and S _vap = 88.2 J K ⁻¹ mol ⁻¹ at 1 bar. Calculate its normal boiling point (where G = 0 ). 2026Which of the following statements regarding spontaneous process is NOT true? 2026Calculate H for a reaction, 2X_ (g) + Y_ (g) 2Z_ (g) at 298 K if U = -10.5 kJ and R = 8.314 J K ⁻¹ mol ⁻¹ . 2026500 mL of nitrogen gas and 750 mL hydrogen gas were allowed to react at 1 bar pressure according to reaction, N _ 2(g) + 3 H _ 2(g) 2 NH _ 3(g) What is PV type of work done during 2026The relationship between H and U for the reaction, PCl ₃(g) + Cl ₂(g) PCl ₅(g) is given as 2026What would be the heat released in kJ when 450 cm ^3 of 0.02 M H ₂ SO ₄ is mixed with 650 cm ^3 of 0.1 M NaOH ? (Heat of neutralization of H ₂ SO ₄ and NaOH is -114 kJ/mol of H ₂ S 2026Identify from following reactions that it takes place with H = U . 2026Calculate the work done in the following reaction at 300 K , A (g) + B (g) = 2 C (g) [R = 8.314 JK ⁻¹ mol ⁻¹] 2026 Full Thermodynamics (C) list All NEET PYQs