Which of the following is NOT a common solvent used as a Class B precursor?

The correct answer is that ephedrine is not a common solvent used as a Class B precursor. In the context of pharmacy and drug manufacturing, Class B precursors are substances that can be used in the synthesis of controlled substances. Solvents, on the other hand, are typically chemicals that facilitate the dissolution of other substances during the chemical processes.

Ephedrine is primarily classified as a precursor itself, specifically for the synthesis of methamphetamine and other amphetamines, rather than a solvent. Its role is more aligned with being a compound that can lead to the production of controlled substances, which is different from the role of solvents in chemical reactions.

In contrast, solvents like acetone, sulphuric acid, and ethyl ether are commonly used in various chemical processes, including reactions involving Class B precursors. Acetone and ethyl ether are organic solvents frequently employed due to their ability to dissolve a wide range of organic compounds. Sulphuric acid, while mainly an acidic reagent, can also act in reactions involving solvent properties due to its highly polar nature.

Understanding the classification of substances in the context of pharmacy law and chemistry is essential for identifying their roles in synthesis and regulatory compliance.