Hydrochloric acid solutions containing methanol or mixtures involving hydrogen chloride dissolved in methanol do not possess a single distinct CAS number because they are categorized as mixtures rather than pure chemical substances. Instead, individual components are tracked separately: pure methanol is designated under CAS 67-56-1, while hydrogen chloride gas dissolved in aqueous solution is registered under CAS 7647-01-0. Laboratories handling methanolic HCl reagents reference individual component safety sheets for compliance.