Question

Write formula of the following compound: Mercury (II) chloride

Answer 1

:Hint:We know that the rules for building the formula for a compound are, first, we write the symbols of the radicals involved side by side, with their valencies at the top, the positive radical to the left and the negative radical to the right. Secondly, we have to remove the common factor, if there is any, to get a simple ratio of the valencies of combining radicals. And lastly, we criss cross the valencies i.e. we shift the valencies crosswise to the lower right of radical.

Complete answer:
In the given compound, the oxidation state of \[Hg\] is II and we also know that the valency of \[Cl\] is 1. Thus, the molecular formula of the compound will be – \[Hg\left( {II} \right)C{l_2}\] . It consists of one mercury (II) cation \[\left( {H{g^{ + 2}}} \right)\] and two chloride anions \[\left( {C{l^{ - 1}}} \right)\] .
Mercury is in \[ + 2\] state and Chlorine is in \[-1\] state.
\[H{g^ + } + 2C{l^ - } \to HgC{l_2}\]

Therefore, the formula for mercury (II) chloride is \[HgC{l_2}\] .

Note:
The monoisotopic and exact mass of \[HgC{l_2}\] is \[271.908\dfrac{g}{{mol}}\] . Mercuric chloride cannot be obtained naturally and that is the reason it is produced chemically. It is a crystalline solid which is white in colour and has no odor. It is readily soluble in hot water, ethyl acetate, acetone, and ethanol but poorly soluble in cold water and it slightly dissolves in benzene and pyridine. It is an extremely toxic compound and is considered fatal when it comes in contact with the skin, eyes and causes severe damage. The other names of mercury (II) chloride are mercury dichloride, mercuric chloride, corrosive sublimate.