Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron)?

Copper is preferred over steel for hot water tanks due to several key properties:

1. Corrosion Resistance: Copper is significantly more resistant to corrosion than steel, especially in the presence of hot water. Steel, particularly in the presence of oxygen and water, is susceptible to rusting (oxidation). This rust can contaminate the water and eventually compromise the structural integrity of the tank. Copper's inherent resistance to corrosion means it will last much longer with less maintenance.

2. Bacteriostatic Properties: Copper possesses natural bacteriostatic properties, meaning it inhibits the growth of bacteria. While not a complete sterilization method, this property helps to maintain better water quality compared to steel tanks, which offer no such inherent protection.

3. Thermal Conductivity: Copper is an excellent conductor of heat. While this isn't the primary reason for its use in hot water tanks (as insulation is crucial), its good thermal conductivity helps ensure even heating of the water and reduces energy waste compared to less conductive materials.

4. Ductility and Malleability: Copper is easily shaped and formed, making it relatively simple and cost-effective to manufacture into hot water tanks. Steel, while also workable, can require more complex manufacturing processes.

5. Long Lifespan: The combination of corrosion resistance and inherent material strength translates into a significantly longer lifespan for copper hot water tanks compared to steel alternatives. This longer lifespan offsets the potentially higher initial cost of copper.

In summary, while steel might be initially cheaper, the superior corrosion resistance, bacteriostatic properties, and longer lifespan of copper make it the more economical and practical choice for hot water tanks in the long run.