why silver does not rust if we keep it outside many days than in iron?
Silver is least reactive metal which cannot even react with acid and water therefore do not rust, if kept open in contact of air and moisture.
Why does aluminium not rust at the same rate as iron?
If rusting of iron is a chemical change than how it converts back to its original form (iron). As I have seen that if we pore cold drinks on rusting iron and keep it for sometimes. And then if we wash the iron with water than it will convert back to its original form. I have seen with my own eyes......