The ionisation isomer of $$\mathrm{[Cr(H_2O)_4Cl(NO_2)]Cl}$$ is

In the Newman projection for 2,2-dimethylbutane, X and Y can, respectively, be

In the reaction

The intermediate(s) is(are)

Copper is the most noble of the first row transition metals and occurs in small deposits in several countries. Ores of copper inculcated chalcanthite (CuSO$$_4$$ . 5H$$_2$$O), atacamite (Cu$$_2$$Cl(OH)$$_3$$), cuprite (Cu$$_2$$O), copper glance (Cu$$_2$$S) and malacite (Cu$$_2$$(OH)$$_2$$CO$$_3$$). However, 80% of the world copper production comes from the ore of chalcopyrite (CuFeS$$_2$$). The extraction of copper from chalcopynite involves partial roasting, removal of iron and self-reduction.

Partial roasting of chalcopyrite produces