Question

Order of boiling point and melting point of $Zn,Cd,Hg,$ respectively is:

• A. $Zn>Cd>Hg$
• B. $Hg>Cd>Zn$
• C. $Hg=Cd=Zn$
• D. None of the above

Answer 1

The correct option is A $Zn>Cd>Hg$

	Boiling point	Melting point
$Zn$	$1180K\left({907}^{o}C\right)$	$693K\left({120}^{o}C\right)$
$Cd$	${766.8}^{o}C$	${321}^{o}C$
$Hg$	$630K\left({357}^{o}C\right)$	$234K(-{39}^{o}C)$

$\Rightarrow Zn,Cd,Hg$ don't have lone pair of electrons. So, there is no interaction with neighbour atoms. So, their melting point and boiling points are less.

$\therefore Zn>Cd>Hg$ for both boiling point & melting point.