Q. Consider the following methods for preventing the rusting of iron:

1. Painting
2. Galvanisation
3. Electrolytic refining
4. Alloying

Which of the above methods are effective in preventing rusting of iron?
Answer: Only 1, 2 and 4
Notes: Painting, galvanisation, and alloying effectively prevent the rusting of iron by creating barriers or altering chemical properties. Electrolytic refining is a purification process used for metals, not for preventing rust. Therefore, the correct options are 1 (Painting), 2 (Galvanisation), and 4 (Alloying), but not 3.