The fluid property, due to which, mercury does not wet the glass is
The fluid property, due to which, mercury does not wet the glass is
Select an option to attempt
Correct Answer: Option D
Explanation
Mercury (Hg) is unique among metals in being liquid at room temperature (mp =, bp =). Its non-wetting of glass is due to SURFACE TENSION. Mercury has the highest surface tension of any common liquid (at 20°C, compared to water = 72 mN/m). The cohesive forces between Hg atoms (metallic bonding/van der Waals) greatly exceed the adhesive forces between Hg and glass (). When placed on glass, Hg minimises surface area by beading up with a convex meniscus (contact angle), unlike water on glass (contact angle near 0°, concave meniscus). High surface tension also means Hg in a capillary tube shows depression (not elevation as water does).