(a(i))[1]
State one gas that is the chief component of natural gas.
(a(ii))[1]
State one gas that causes both photochemical smog and acid rain.
(a(iii))[1]
State one gas that is unsaturated.
(a(iv))[1]
State one gas that has monatomic particles.
(a(v))[1]
State one gas that reduces iron(III) oxide in a blast furnace.
(b)[2]
Nitrogen dioxide, $\text{NO}_2$, and carbon monoxide are eliminated from a car exhaust by a catalytic converter. Write the symbol equation for this reaction.