2 mL each of concentrated HCl, HNO 3 and a mixture of concentrated HCl and concentrated HNO 3 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
3:1 solution of HCl and HNO 3 is called Aqua regia and it is able to dissolve gold.
So, the correct option is (b) Au