Question

Explain why the Canadian Parliament Buildings have a blue/green coloured roof.

Answer 1

The reason the buildings’ roof looks blue/green is the material used for design. The used substance is copper and that makes the roofs more resistant to corrosion and durable. Copper goes through oxidation processes that form a protective layer on its surface. This protective layer is blue because it consists of copper carbonate and oxide:
2 Cu + O2 = 2 CuO
CuO + CO2 = CuCO3