Question

give reason for the following :-)
most air and acidic gases are not good for some metals.

Answer 1

moist air can react with metals to form oxides and acidic gases can react with the metals to form hydrogen gas and salt which will change the properties of the metals.

Answer 2

Metals are one of the most common objects which reacts with different acidic gases.

And some of the metals are highly reactive with the acidic gases or normal atmospheric air.

And in these reactions the metals are often harmed by the gases.

That's why acidic gases are not good for some highly reactive metals.