Question

The three way catalytic converter is the most ideal type of catalytic converter since it can convert not only CO and HC, but also ............... into non-polluting substances.

Hint:

Tip: TWC = treats CO + HC + NOx → cleaner air!

Answer 1

A three-way catalytic converter (TWC) is a key emission control device in modern vehicles.
It reduces three major pollutants from exhaust gases: Carbon Monoxide (CO), Hydrocarbons (HC), and Nitrogen Oxides (NOx).
While CO and HC are oxidized to form CO₂ and water, NOx is reduced to harmless nitrogen and oxygen.
This makes the three-way converter very effective in controlling vehicle emissions.
CO₂ and O₂ are not pollutants that need converting.
SO₂ is handled differently in some diesel systems, not by standard TWCs.
Therefore, the correct answer is NOx.