Why are the food cans coated with tin instead of zinc ?

Food cans are coated with tin because it is less reactive than zinc. In the chemical reactivity series, zinc is more reactive than tin. If food cans were coated with zinc, the metal would react with the organic acids naturally present in food items (such as citric acid in fruits) to form toxic metal compounds, which could lead to food poisoning. Tin, being less reactive, does not easily react with food acids, providing a safe and non-toxic protective layer that prevents the underlying steel or iron from corroding and contaminating the contents. While factors like cost and melting point exist, chemical stability and safety are the primary reasons for using tin in food packaging.