Nitrogen's Atmospheric Reactivity

Steps:

• Evaluate A: Check if NH4+ acts as a base via lone pair donation.
• Evaluate B: Recall photochemical smog components and NO's reactions.
• Evaluate C: Identify NO2's catalytic role in SO2 oxidation.
• Evaluate D: Determine N2's unreactive nature from its bonding.

Why C is correct:

• NO2 catalyzes SO2 oxidation to SO3 via the reaction 2NO2 + SO2 → 2NO + SO3, then NO regenerates NO2, forming sulfuric acid in acid rain.

Why the others are wrong:

• A: NH4+ is acidic, releasing H+ in water (NH4+ ⇌ NH3 + H+), not basic.
• B: NO reacts with O2 and hydrocarbons in smog, but PAN (a reservoir) decomposes to NO2, not directly with NO.
• D: N2's unreliability stems from the strong N≡N triple bond (945 kJ/mol), not dipole-dipole attractions, as N2 is nonpolar.

Final answer: C