JEE Main · 2019 · 10 Apr 2019 · Shift 2 · General Principles and Processes of Isolation of Metals

Aniline is used in froth flotation as a froth stabiliser, keeping the mineral-laden foam intact, so that statement is sound. The rest do not hold up: zincite is the oxide $\mathrm{ZnO}$, not a carbonate; titanium is purified by the van Arkel or Kroll route rather than zone refining, which is reserved for semiconductors like silicon and germanium; and sodium cyanide is in fact central to silver extraction, dissolving the metal as $[\mathrm{Ag}(\mathrm{CN}){}_2]{}^{-}$.