Question

Type of corrosion taking place when metal comes in contact with acids

Answer 1

1. The eating up of metals by the action of air , moisture or a chemical (such as an acid) on their surfaces is called corrosion.
2. Most of the metals corrode when they are kept exposed to damp air(or          moist air). 
3. When an iron object is kept in damp air for a considerable time , then a          red-brown substance called 'rust' is formed on its surface.
4.Corrosion of iron is a continuous process which ultimately eats up the     whole iron object .
5.The corrosion of iron is called rusting . while other metals are said to                'corrode', iron metal is said to 'rust'.

Answer 2

Actually corrosion word is used for the metals when they got damage or corroded due to present of air.
But when metal comes in contact with the acids they are corroded also because of the quick action of acids and the chemical reactions between them. This type of corrosion sometimes may also be called as the acidic corrosion.
They corrosion is harmful for metals because it damage them and decrease their durability.  
Hope this will help you.