What color is hydrogen chloride (HCl) and what is its characteristic smell?

Hydrogen chloride (HCl) is a colorless gas that can sometimes appear slightly yellow due to the presence of impurities or as a consequence of light scattering. Its characteristic smell is pungent and irritating, which corresponds to the nature of many acidic gases. This strong, sharp odor is associated with its corrosive properties and the effects it can have on mucous membranes upon inhalation. Understanding the properties of hydrogen chloride is crucial in various applications, particularly in industrial and laboratory settings where safety protocols must consider its volatility and potential hazards.