JEE MainChemistryp Block Elements (Group 15, 16, 17 & 18)
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The formation of nitric oxide (NO) from N₂ and O₂ in the atmosphere occurs naturally only during lightning strikes. Reason (R): The reaction between N₂ and O₂ to form NO is highly exothermic but requires a very high activation energy to break the strong N N triple bond. In the light of the above st
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A).
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A).
- C(A) is not correct but (R) is correct.
- D(A) is correct but (R) is not correct.
Correct answer
D. (A) is correct but (R) is not correct.
Step-by-step solution
Assertion (A) is correct. Dinitrogen and dioxygen are the major constituents of air, but they do not react at normal temperatures. They react to form nitric oxide (NO) only at very high temperatures (around 2000 K ), which is provided naturally by lightning strikes. Reason (R) is incorrect. The reaction N₂(g) + O₂(g) 2NO(g) is highly endothermic, not exothermic. The energy required to break the strong N N and O=O bonds is much greater than the energy released upon the formation of N-O bonds. Thus, (A) is correct bu