What is the ratio of HNO₃ and HCl in aqua regia? What are the applications of aqua regia?

Aqua regia is a powerful mixture of acids, specifically composed of hydrochloric acid (HCl) and nitric acid (HNO₃). The typical ratio used in aqua regia is 3 parts HCl to 1 part HNO₃. This combination allows it to dissolve noble metals like gold and platinum, which are resistant to other acids.

Uses of Aqua Regia

Aqua regia has several important applications, including:

• Dissolving Metals: It is primarily used to dissolve precious metals for refining and analysis.
• Cleaning Laboratory Glassware: Aqua regia can effectively remove organic residues and contaminants from glassware.
• Analytical Chemistry: It is utilized in various chemical analyses, especially in the preparation of samples for spectroscopic techniques.
• Etching and Engraving: The solution is used in the etching of metals in the manufacturing of electronic components.

Due to its highly corrosive nature, aqua regia must be handled with extreme caution, using appropriate safety measures.