Question

which of the following is not a combustion reaction?
a li(s) + o₂(g) → li₂o(s)
b c₆h₁₂(l) + o₂(g) → co₂(g) + h₂o(l)
c c(s) + o₂(g) → co₂(g)
d no(g) + o₃(g) → no₂(g) + o₂(g)

Explanation:

Combustion reactions typically involve a substance reacting with oxygen (\(O_2\)) to produce oxides and often release heat. In option a, lithium (\(Li\)) reacts with \(O_2\) to form lithium oxide (\(Li_2O\)), which is a combustion reaction. In option b, \(C_6H_{12}\) (a hydrocarbon) reacts with \(O_2\) to form \(CO_2\) and \(H_2O\), which is a classic combustion reaction of a hydrocarbon. In option c, carbon (\(C\)) reacts with \(O_2\) to form \(CO_2\), a combustion reaction. In option d, \(NO\) reacts with \(O_3\) (ozone) to form \(NO_2\) and \(O_2\). This is not a reaction with \(O_2\) (the typical oxidant in combustion) in the sense of a combustion reaction (also, combustion reactions of common fuels like hydrocarbons, metals etc. usually have a more exothermic and characteristic product - formation pattern related to \(O_2\) as the main oxidant).

Answer:

d. \(NO(g)+O_3(g)\to NO_2(g) + O_2(g)\)