2 mL each of concentrated HCl, HNO3 and a mixture of concentrated HCl and concentrated HNO3 in the ratio of 3 : 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C respectively. The metal could be [NCERT Exemplar Problems]
(a) Al
(b) Au
(c) Cu
(d) Ag
Answers
Answer:
As per the given question, the Aqua regia is the given mixture to test the metals in test tubes A, B and C. A mixture of three parts of concentrated hydrochloric acid and one part of concentrated nitric acid(Aqua regia - 3:1 ratio) is capable of dissolving gold.
Gold is a noble metal that cannot dissolve in dilute acids and dissolves only in aqua regia.
Hence, the metal in test tube C must be gold (Au). The correct option is (B).
Answer:
As per the given question, the Aqua regia is the given mixture to test the metals in test tubes A, B and C. A mixture of three parts of concentrated hydrochloric acid and one part of concentrated nitric acid(Aqua regia - 3:1 ratio) is capable of dissolving gold.
Gold is a noble metal that cannot dissolve in dilute acids and dissolves only in aqua regia.
Hence, the metal in test tube C must be gold (Au). The correct option is (B).
Explanation: