The combustion of a hydrocarbon fuel does not produce?

Question

a. H2
b. H2O
c. CO
d. CO2

Answer 1

a) H2

From wikipedia:

Burning hydrocarbons
See also: Flue gas emissions from fossil fuel combustion
Hydrocarbons are one of the Earth's most important energy resources. Hydrocarbons are currently the main source of the world’s electric energy and heat sources (such as home heating) because of the energy produced when burnt. Often this energy is used directly as heat such as in home heaters, which use either oil or natural gas. The hydrocarbon is burnt and the heat is used to heat water, which is then circulated. A similar principle is used to create electric energy in power plants. Hydrocarbons (usually coal) are burnt and the energy released in this way is used to turn water into steam, which is used to turn a turbine that generates energy.

In an ideal reaction, the waste would be only water and carbon dioxide, but because the coal is not pure or clean there are often many toxic byproducts such as mercury and arsenic. Also, incomplete combustion causes the production of carbon monoxide (CO) which is toxic to humans due to its tendency to bind to hemoglobin molecules in the bloodstream. Once bound, CO does not allow oxygen to be carried by hemoglobin and can result in hypoxia. Incomplete combustion also has a byproduct of carbon in the form of soot.