Correct Option
The correct option isTin is less chemically reactive than iron.
Explanation
Electroplating is the process of depositing a layer of one metal onto another using an electric current. This technique is widely used to modify the surface properties of an object, such as resistance to corrosion or chemical reactivity. In the context of food storage containers, the chemical interaction between the metal and the food is the primary concern.
Detailed Analysis
- Reactivity of Iron: Iron is a chemically reactive metal. When exposed to moisture, air, or the organic acids naturally present in food, iron tends to corrode (rust) and react chemically. This interaction can lead to food spoilage and potential toxicity.
- Properties of Tin: Tin is significantly less reactive than iron. It is resistant to corrosion and does not easily react with food acids or moisture.
- Mechanism of Protection: By electroplating a thin layer of tin over iron, the underlying iron is isolated from the food. This prevents the iron from rusting or contaminating the food contents.
- Comparison with other options:
- Tin is physically harder than iron. Hardness: While physical properties matter for structural integrity, hardness is not the primary reason for coating food containers; chemical safety is.
- Tin is more chemically reactive than iron. Higher Reactivity: If tin were more reactive than iron, it would corrode faster and contaminate the food, defeating the purpose of the coating.
- Tin is a better thermal conductor than iron. Thermal Conductivity: While thermal properties are relevant for cooking utensils, they are not the deciding factor for storage containers.
Key Takeaway: Tin is used for electroplating food containers because it is less chemically reactive than iron, thereby protecting the food from spoilage and the container from corrosion.