Question

Why is HCL not used to recover the original colour of the statue of liberty?

Answer 1

The green color of the Statue of Liberty is due to the oxidation of the copper sheathing, called patina. Most metals develop a patina, as well as wood, plastic, everything that is used and exposed to the air. The shiny wear marks on wood and plastic items you handle every day? That's patina, caused by the oils and acids in your skin reacting with the surfaces of the wood and plastic.
Patina serves two purposes-

• Protects the material it is covering from further damage of corrosion and weathering.
• Makes the material aesthetically pleasing.

Because of these two reasons, people don't remove patina when it appears as well as want items to be patina covered if they are buying as an antique piece.

Same is the case with the Statue of Liberty