Assertion: Nitrogen and Oxygen are the main components in the atmosphere but these do not react to form oxides of nitrogen.
Reason: The reaction between nitrogen and oxygen requires high temperature.
(C) Nitrogen is not react in normal condition because N2 has triple bond which provide inert nature to N2
Assertion: Nitrogen and Oxygen are the main components in the atmosphere but these do not react to form oxides of nitrogen.
Reason: The reaction between nitrogen and oxygen requires high temperature.
Let's analyze this step by step:
Step 1: Understanding the Assertion
The assertion states that nitrogen (N2) and oxygen (O2) are the main atmospheric components but don't react under normal conditions to form nitrogen oxides. This is factually correct - our atmosphere contains approximately 78% N2 and 21% O2, yet they coexist without significant reaction at ambient temperatures.
Step 2: Understanding the Reason
The reason states that this reaction requires high temperature. This is also correct. The formation of nitrogen oxides from elemental nitrogen and oxygen is an endothermic process with a high activation energy barrier. The reaction:
has a positive ΔG° at room temperature and only becomes spontaneous at very high temperatures (above approximately 2000°C). This is why nitrogen oxides form during high-temperature combustion processes like in automobile engines or lightning strikes, but not under normal atmospheric conditions.
Step 3: Evaluating the Relationship
The reason correctly explains why the assertion is true. The high temperature requirement is the fundamental chemical reason why nitrogen and oxygen don't react under normal atmospheric conditions despite their abundance.
Final Answer: Both assertion and reason are correct, and the reason is the correct explanation for the assertion.
Chemical Kinetics and Thermodynamics: This question involves understanding both kinetic and thermodynamic barriers to reaction. While the reaction is thermodynamically unfavorable at room temperature (positive ΔG), it also has a high activation energy that requires high temperatures to overcome.
Atmospheric Chemistry: Nitrogen oxides play crucial roles in atmospheric chemistry, contributing to smog formation, acid rain, and ozone depletion, but their natural formation is limited to high-energy events.
The temperature dependence of reaction spontaneity is governed by the Gibbs free energy equation:
For endothermic reactions (ΔH > 0), increasing temperature makes ΔG more negative, favoring product formation.