NEET 2021 Chemistry Question 65 Solution

Mercury ($Hg$, atomic number 80) is the only metallic element that exists in the liquid state at standard room temperature ($25^\circ\text{C}$ / $298\text{ K}$), having a melting point of $-38.83^\circ\text{C}$.

NCERT categorizes metal refining processes based on physical properties: - Distillation: Used specifically for metals with low boiling points, such as Zinc ($Zn$) and Mercury ($Hg$). The impure volatile metal is vaporized and condensed as pure distillate, leaving non-volatile impurities behind. - Electrolysis: Applied to reactive or common industrial metals like copper, aluminum, and gold. - Zone Refining: Applied to ultra-pure semiconductors (Germanium, Silicon, Boron, Gallium, Indium). - Chromatography: Utilized when elements to be separated are available in minute quantities and exhibit close chemical similarities.

Distillation is the designated metallurgical method to obtain highly pure mercury, corresponding to Option (3).