JEE Main2015ChemistryThermodynamics (C)Actual
The following reaction is performed at 298   K . 2 N O g + O 2 g ⇌ 2 N O 2 g The standard free energy of the formation of N O g is 86 . 6   kJ   mol - 1 at 298   K . What is the standard free energy of the formation of N O 2 g at 298   K ? ( K P = 1.6 × 10 12 )
Options
- A0.5 [ 2 × 86,600 - R 298 ln ⁡ ( 1.6 × 10 12 ) ]
- BR 298 ln 1.6 × 10 12 -86,600
- C86,600 + R 298 ln ( 1.6 × 10 12 )
- D86,600 - ln ( 1.6 × 10 12 ) R ( 298 )
Correct answer
A. 0.5 [ 2 × 86,600 - R 298 ln ⁡ ( 1.6 × 10 12 ) ]
Step-by-step solution
Δ G reac ∘ = - 2.303 RT log K P = - RT ln K P = - R 2 9 8 ln  1.6 × 1 0 1 2 Δ G reac ∘ = 2 Δ G f NO 2 ∘ - 2 Δ G f NO ∘ ⇒ - R 298 ln  1.6 × 10 12 = 2 Δ G f NO 2 ∘ - 2 × 86.6 × 1 0 3 ⇒ 2 Δ G f NO 2 ∘ = - R 2 9 8 ln 1.6 × 1 0 1 2 + 2 × 86,600 Δ G f NO 2 ∘ = 86,600 - R 2 9 8 2 ln 1.6 × 1 0 1 2 = 0.5 2 × 86,600 - R 2 9 8 ln 1.6 × 1 0 1 2