BITSAT2017Chemistryp Block Elements (Group 15, 16, 17 & 18)Actual
For the reaction N 2 O 4 g ⟶ 2 NO 2 g
Options
- AΔH > ΔE
- BΔH < ΔE
- CΔH = ΔE
- DΔH = 0
Correct answer
A. ΔH > ΔE
Step-by-step solution
∵   ΔH = ΔE + Δn g RT and Δn g (for the given reaction) = 2 - 1 = + 1 ∴   ΔH > ΔE In exothermic reactions, heat from the system is lost to the surrounding. For such reactions, ∆H is negative. In endothermic reactions, heat is absorbed by the system from the surroundings. For such reactions, ∆H is positive.