HCl and Metal

[Asian]

Why when HCl reacts with a metal the metal changes colors.

[Darkblade48]

Metals don't change colour upon reacting with hydrochloric acid; unless, perhaps, you're thinking of transition metals and their salts?

[Asian]

so if you are looking for wether or not hcl is reactive with a metal, a change in color of the metal would not be something to look for?

[Darkblade48]

so if you are looking for wether or not hcl is reactive with a metal, a change in color of the metal would not be something to look for?

I would not look for a colour change, no. I can think of several metals that will react with hydrochloric acid that do not elicit a colour change.

[woelen]

Why when HCl reacts with a metal the metal changes colors.

Usually there seems to be a change of color (e.g. if you put a copper coin in acid, it turns much more reddish), but that is due to dissolving of an oxide-layer, or more generally, a layer of impurities and tarnished metal. Most metals do tarnish in contact with air, especially if they are humid, or handled by humans and grease and dirt stick to the metal (e.g. coins, tools).

[John Cuthber]

It depends on what you mean by colour.

Is "silver" a colour?

If you put zinc, which is silver coloured ,into HCl it will dissolve to give zinc chloride, which is colourless (and hydrogen).