How is the reaction between Aluminium and Mercury Chloride possible?

Aluminium is coated with a thin layer of Aluminium Oxide. Why then do we write the reaction as

2Al + 3HgCl2 → 2AlCl3 + 3Hg

Shouldn't we first write an equation showing how HgCl2 reacts with Al2O3 ?

1 Answer
Mar 19, 2016

Aluminium is first scraped with sand paper to remove the oxide layer then it reacts with mercury chloride and displaces it as mercury is below aluminium in the reactivity series.