InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
Explain the chemical reaction pf Aqua regia with Gold/silver/copper/platinum? |
| Answer» The term ‘aqua regia’ is Latin for ‘royal water’.Aqua regia is a very strong acid formed by the combination of concentrated nitric acid and concentrated hydrochloric acid, both of which are strong acids.It is generally used to remove metals like gold and platinum from substances, especially in microelectronics and micro-fabrications labs.It is usually a yellow, reddish-orange, fuming liquid and has a rapidly changing composition.It is primarily popular for its ability to dissolve gold, palladium and platinum, all of which dont react easily with chemicals.\xa0The reason aqua regia can dissolve gold (and metals like platinum and palladium) is that each of its two component acids(i.e., hydrochloric acid and nitric acid) carries out a different function. While nitric acid is an excellent oxidizing agent, the chloride ions from the HCl form coordination complexes with gold ions, thereby removing them from the solution.\xa0The reduction of the concentration of Au3+\xa0ions shifts the equilibrium towards the oxidized form.\xa0The gold present in aqua regia dissolves completely to form chloroauric acid (HAuCl4). | |