Question

What toxic, odorless gas is produced by a running engine?

Answer 1

`"Carbon monoxide.............."`

Explanation:

The complete combustion of hydrocarbons, hexanes for instance, can be represented by the following reaction:

`"C"_6"H"_14"(l)" + 19/2"O"_2"(g)" rarr "6CO"_2"(g)" + "7H"_2"O(l)"`

We could represent incomplete combustion by assuming that SOME of the hydrocarbon was combusted to give carbon monoxide:

`"C"_6"H"_14"(l)" + "9O"_2"(g)" rarr "5CO"_2"(g)" + "CO(g)" + "7H"_2"O(l)"`

Alternatively, under conditions of deficient oxygen, some carbon, and some carbon monoxide may be generated:

`"C"_6"H"_14"(l)" + "8O"_2"(g)" rarr "4CO"_2"(g)" + "CO(g)" + "C(s)"+"7H"_2"O(l)"`

In terms of oxidation number, what is the difference between `"C"`, `"CO"`, and `"CO"_2`?