Which of the following chemicals consists mainly of hydrocarbons?

The correct answer is mineral oil, which is primarily composed of hydrocarbons. Hydrocarbons are organic compounds made up exclusively of hydrogen and carbon atoms. In the case of mineral oil, it is derived from refining crude oil and consists largely of saturated hydrocarbons, making it a common ingredient used in cosmetics and skincare products for its moisturizing properties and ability to create a barrier on the skin.

Stearic acid, while it does contain hydrocarbons as part of its structure, is classified as a fatty acid and has a carboxylic acid functional group, which disqualifies it from being primarily a hydrocarbon. Carbon dioxide, on the other hand, is a simple molecule made up of carbon and oxygen atoms, distinctly lacking in hydrogen. Sodium hydroxide is an inorganic compound that consists of sodium, oxygen, and hydrogen ions in the form of hydroxide, also not fitting the criteria for hydrocarbons. Thus, mineral oil is the only option that is predominantly made up of hydrocarbons.