Hydrochloric acid（HCL）

Hydrochloric acid is an aqueous solution of hydrogen chloride (HCl), which has a pungent odor. Due to the volatility of concentrated hydrochloric acid, the hydrogen chloride gas emitted reacts with water vapor in the air to form small droplets of hydrochloric acid, resulting in white mist. Hydrochloric acid is freely miscible with water and ethanol, while hydrogen chloride can dissolve in many organic solvents.