Which of the following is used to dissolve noble metals?
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Nitric acid
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Hydrochloric acid
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Sulphuric acid
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Aqua regia
D
Correct answer
Explanation
Aqua regia (Latin for 'royal water') is a mixture of nitric acid and hydrochloric acid in 1:3 ratio. It can dissolve gold and platinum, which are 'noble' metals that resist most other acids. The chloride ions form soluble complexes with noble metal ions.