Subject :NSO Class : Class 6
Read the given passage and fill in the blanks by choosing an appropriate option.
Iron nails when new are grey and bright. When exposed to (i), they get covered with a (ii) coating. This process is called (iii) and it is a (iv) change.
| (i) | (ii) | (iii) | (iv) | |
| A | Moist air | Grey | Corrosion | Chemical, reversible |
| B | Air and water | Reddish brown | Rusting | Chemical, irreversible |
| C | Oxygen in air | Green | Rancidity | Physical, irreversible |
| D | Nitrogen in air | Reddish brown | Galvani-sation | Chemical, irreversible |