If you are studying chemistry, HNO3 is one of the chemicals that you will hear often. This may be used by your professor in a lot of examples. This colorless liquid may also be used in the lab for experimentation from time to time. How will you know if you are handling HNO3?
This is usually properly labeled so that you will not unintentionally think that this is something else. Nitric acid is very corrosive and it will definitely react with other elements that you will expose it to. You will know if HNO3 is still new if it would remain colorless. The longer that it is stored, the more yellowish it would be.