Nitrogen Oxides Formation via Lightning

Steps:

• Identify processes forming nitrogen oxides (NOx) in natural and man-made environments.
• Evaluate each option against known chemical reactions for NOx production and removal.
• Confirm A matches the high-energy fixation of N2 and O2 during lightning.
• Eliminate B, C, D based on incorrect mechanisms in engines and atmosphere.

Why A is correct:

• Lightning's electrical discharge provides energy to break N≡N bonds, enabling N2 + O2 → 2NO per the endothermic reaction requiring ~180 kJ/mol.

Why the others are wrong:

• B: Catalytic converters reduce NO with CO to N2 + CO2, not combine with CO2.
• C: High combustion temperatures in engines form NOx despite oxygen availability via Zeldovich mechanism.
• D: Atmospheric NO oxidizes to NO2, which reacts with hydrocarbons; SO2 to SO3 involves O2 or OH radicals, not direct NO reaction.

Final answer: A