The extraction of zinc from zinc blende is achieved by

Which of the following pair of metals are extracted by self-reduction from their main ores but do not evolve $H_2$ gas with dilute $H_2SO_4$?

The process,which does not use a catalyst is

Which of the following is not a basic flux?

Observe the following statements:
Statement-$I$: The choice of reducing agent for the reduction of an oxide ore can be predicted by using Ellingham diagram,a plot of $\Delta G^{\ominus}$ vs $T$.
Statement-$II$: According to Ellingham diagram,metal oxide with higher $\Delta G^{\ominus}$ is more stable than the oxide with lower $\Delta G^{\ominus}$.

In the extraction of copper,the slag obtained is mainly composed of........