Question

which metal does not produce hydrogen when added to dilute hydrochloric acid

Answer 1

The products of acid/metal reactions are a salt and hydrogen gas. Some metals are so unreactive that they do not react with dilute acids at all, e.g. copper, silver and gold.

Answer 2

Answer:

Cu, Pt, Au metals does not produce hydrogen when it is added to “dilute hydrochloric acid”.

Explanation:

The production of hydrogen gas from the reaction of metal and acid depends on the reactivity of metal that can be checked in the metal reactivity series. The metal lying above the hydrogen in the reactivity series can liberate hydrogen gas with almost all acids like $\bold{\mathrm{H}_{2} \mathrm{SO}_{4}, \mathrm{HCl},}$ etc.  

On the contrary, the metals which are lying below H in the metal reactivity series cannot do that as they are considered to be less reactive than H. Some of the metals are Cu, Pt, Au, etc.