Question

Write the molecular formula for the following compounds: Mercury(II) chloride

Answer 1

Hint: Write the electronic configuration of mercury in its ground state. Now mercury releases 2 electrons and mercury atoms go into the oxidation state 2. Chlorine atom needs one electron to form a stable anion. Now write the cation as well as the anion such as the electric charge is balanced. With this, you can write the molecular formula of mercury(II) chloride.

Complete step by step solution:
Mercury(II) chloride or mercuric chloride often referred to as corrosive sublimate is the chemical compound of mercury with the halogen atom chlorine.
It is a white crystalline solid which is used in laboratories which are toxic especially to humans. It was earlier used for the treatment of syphilis but is now no longer used due to the toxic nature of mercury element.
Mercuric chloride is used as a catalyst for the conversion of acetylene to vinyl chloride, the monomer of polyvinyl chloride. Along with that, it is occasionally used for the formation of amalgam with metals atoms.
Mercuric chloride does not exist as a simple salt as it is not composed of mere discrete ions. Instead, it is composed of linear triatomic molecules hence has a tendency to sublime.
Since two chloride ions react with the mercury cation, the molecular formula for the compound is $HgC{{l}_{2}}$.

Note: Mercuric chloride exists as a complex compound which is a characteristic feature of d block elements. The compound forms a complex with two incoming chlorine ligands. It forms a tetrahedral coordination complex with the formula ${{[HgC{{l}_{4}}]}^{2-}}$.