posted by Anonymous .
Can anyone help predict the reaction that will take place when Gold is put into a solution of Hydrochloric Acid?
zilch. no reaction.
Au is below hydrogen in the activity series; therefore, gold will not replace hydrogen ion from an acid such as HCl. Au will dissolve in Aqua Regia (royal water) which is a mixture of HCl and HNO3. The HNO3 serves as an oxidizing agent, some gold ions form, and they are then bound up in AuCl4^- complex ions which shifts the reaction to the right and that allows more Au to be oxidized by HNO3.