What will react with acids and produce hydrogen gas?

Metals react with acids to produce hydrogen gas and metallic salts. The rate at which the hydrogen is formed during the reaction depends on the reactivity of the metal involved.

Metals react with acids to produce hydrogen gas. Acids contain hydrogen atoms. For example, in hydrochloric acid hydrogen is bonded to a chlorine atom. Therefore when metals react with acids they take the place of  hydrogen in the acid and therefore form a salt. The displaced hydrogen is then released as a gas. This does not happen with all metals though. The metal has to be higher than hydrogen in the reactivity series for this to occur. The higher up a metal is in the reactivity series, the more likely this metal would form cations (ie release an electron) to participate in a reaction. Therefore if the metal is more willing than hydrogen to participate in a reaction, it would displace hydrogen from the acid. Metals like sodium, calcium and magnesium would easily release hydrogen when reacting with an acid. While silver, platinum and gold would not react with an acid and therefore, would not release hydrogen gas.

Aphysical change is one that you can put in and remove like a ham sandwich. the stuff you put in there can be changem its not permanet. a chemical change is on that can't be change thats permanet. like when you make a cake and bake it. you can't get those ingredients back.