Areaction of a hydrocarbon, in which carbon dioxide and water are produced, is classified as a
a. decomposition reaction.
c. double-displacement reaction.
b. combustion reaction.
d. synthesis reaction.

This is a combustion reaction. Any reaction in which a hydrocarbon decomposes into carbon dioxide and water is classified as combustion. The energy used for the decomposition usually comes from intense heat, which is why combustion of a hydrocarbon almost always is associated with a source of fire.

Ithink this is what you meant. the temperature at which a liquid begins to boil is called the boiling point. the boiling point of water is 212°f or 100°c.  and at that point will start to turn into steam (gas)