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

In which of the following physical processes is the change in entropy ( S ) positive?

Options

  1. ADissolution of CO ₂ gas in water
  2. BDissolution of solid NaCl in water
  3. CCrystallization of sugar from a supersaturated solution
  4. DCondensation of steam to liquid water

Correct answer

B. Dissolution of solid NaCl in water

Step-by-step solution

Entropy is a measure of the degree of randomness or disorder in a system. When solid NaCl dissolves in water, the highly ordered crystal lattice breaks down into free-moving Na ⁺ and Cl ⁻ ions in the solution, which increases the randomness. Hence, S > 0 . For the dissolution of CO ₂ gas in water, the gaseous molecules are confined to the liquid phase, decreasing randomness ( S Crystallization of sugar involves the formation of an ordered solid from a solution, decreasing randomness ( S Condensation of steam conver

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