All metals do not react with acids to produce hydrogen gas. Only those metals which lie above hydrogen react with acids to produce hydrogen gas. Whereas copper, silver, gold, and platinum do not react with acids to produce hydrogen.
Hydrogen and Chlorine react so that they're atoms can have a full outer shell with eight electrons. Hydrogen just has to lose an electron and Chlorine just has to gain an electron, so they react and make Hydrogen Chloride.
I only know 3 metals that react with acids to produce hydrogen. They are Zinc, iron and magnesium. There are 3 acids which react with them: and It will produce hydrogen gas which is the lightest known gas and is flammable :)