acid(f.4 chem)

1. Because concentrated HNO3 will decompose when light occur. 4HNO3 -> 4NO2 + 2H2O + O2. So we keep conc. HNO3 in brown bottle to prevent light. Dilute HNO3 is stable in room temperature and condition, pressure and it won't decompose when light occur so it is no need to keep it in brown bottle.

2. HNO3 is a strong oxdizing agent, especially when it is conc.. This is because nitrate ion NO3-, in a present of hydrogen ion H+, act as a electron accepter.
Because of its strong oxidizing property, it can easily oxidize or skin, clothes. Our skin, body, clothes are mostly contain carbon, HNO3 will oxidize carbon into carbon dioxide. It destory our skin and clothes etc. easily so it become very corrosive.

1. Conc. HNO3 is senstive to light and will decompose, and therefore is stored in brown bottles; dilute HNO3 does not have this property

2. Nitric acid oxidizes your skin and damage your cell, hence corrosive.