Answer:
Stoichiometric compounds are composed of whole number ratios of constituent atoms.
Step-by-step explanation:
In accordance with Dalton's law, when atoms combine to form compounds, they do so in simple whole number ratios.
Hydrocarbons compounds are compounds of hydrogen and carbon. The hydrogen and carbon usually combine in simple whole number ratios. The ratio of hydrogen atoms to carbon atoms in organic compounds is never fractional.
Combination of 6 hydrogen atoms and 2.5 carbon atoms do not represent simple whole number ratio of combination of constituent atoms hence it is not possible to make such a compound. There can never be a hydrocarbon containing the said ratio of hydrogen to carbon atoms.