Question

Why do Noble Metals do not react with dilute acids?? Please answer Thank you

Answer 1

See the discussion that follows...

Explanation:

There are a few ways one could account for this. I will use the concept of reduction potentials.

Each of the noble metals has a relatively large positive reduction potential, which means it takes a strong oxidizing agent to cause the oxidation of these metals.

Being a strong acid does not necessarily make a chemical a strong oxidizing agent. The `H^+` ion produced by `HCl` is not a strong oxidizing agent, and does not react with metals like Ag or Au.

On the other hand, nitric acid produces both `H^+` and `NO_3^-` ions, which taken together do make a strong oxidizing agent. Thus, nitric acid will dissolve silver, but not gold.

This does not attempt to explain why these chemicals are strong oxidizers, but should provide a concept that accounts for a reaction in one case, but no reaction in another.