Also, after I had finished the experiment, I took the egg out, washed it off and placed it in a container of water.
Acids eat away at things by releasing hydrogen ions in water.
They are very reactive with almost substance that is known because they are very unstable. All elements can be found in their stable states. This means that they have the same number of protons in their nucleus as they have electrons surrounding their nucleus. An ion is an element that has either gained or lost an electron. This means that they have become unstable.