What is the product formed when cumene is air oxidised in presence of Co-naphthenate and further treated with dilute acid?

Identify the use of polystyrene for household purposes.

Identify compound $$\mathrm{A}$$ in following reaction

Benzene + Ozone (excess) $$\rightarrow$$ Benzenetriozonide $$\xrightarrow{\mathrm{A}}$$ Glyoxal

Which from following pairs of compounds is an example of metamerism?