Reactions of gold and platinum
Gold is unaffected by air, water, alkalis and all acids except a mixture of hydrochloric acid and nitric acid known as nitrohydrochloric acid (one of the strongest acids in existence).
Platinum is extremely unreactive. It’s not interested in forming bonds with other elements at all, and only does so if forced.
Platinum does not react with dilute acids.
Platinum can be made to react with very strong acid (nitrohydrochloric acid), but only if it is heated. Essentially, you have to force it to react against its will!