JEE Advanced2022ChemistryThermodynamics (C)Actual
The correct option(s) about entropy (S) is(are) [ R = gas constant, F = Faraday constant, T = Temperature]
Options
- AFor the reaction, M s + 2 H + aq → H 2 g + M 2 + aq , if dE cell   dT = R F then the entropy change
- BThe cell reaction, Pt s ∣ H 2 g , 1   bar H + aq , 0 . 01 M ‖ H + aq , 0 . 1 M H 2 g , 1 bar
- CFor racemization of an optically active compound, Δ S > 0
- D( S >0 ), for ( [ Ni ( H ₂ O ) 6 ]²⁺+3 en [ Ni ( en )₃]²⁺+6 H ₂ O ) (where en (= ) ethylenediamine)
Correct answer
B. The cell reaction, Pt s ∣ H 2 g , 1   bar H + aq , 0 . 01 M ‖ H + aq , 0 . 1 M H 2 g , 1 bar
Step-by-step solution
(A) M s + 2 H + aq → H 2 g + M 2 + aq if dE cell   dT = R F Δ S = nF dE dT = 2   F R F = 2 R (B) E cell   = - 2 . 303 RT F log 0 . 01 0 . 1 = 2 . 303 RT F dE cell   dT = 2 . 303 R F ∴ Δ S = nF dE dT > 0 It is an entropy driven process. (C) It is correct Racemisation is a thermodynamically favourable method, and it proceeds spontaneously if a suitable pathway is accessible for the interconversion of the enantiomers. During racemisation of optically active compound, disor