Question

<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> <!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> The formula of aluminium oxide is ${\mathrm{Al}}_2{O}_3$. If aluminium forms its chloride, what will be the formula of that compound?

Answer 1

<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> <!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> In ${\mathrm{Al}}_2{O}_3$, the valency of aluminium is 3 and oxygen is 2.
The valency of Chlorine is 1. [1 Mark]
So, for a chloride of aluminium:
Symbol Al Cl
Valency 3 1
On interchanging the valencies of each element and writing them down as subscripts, we get the formula – ${\mathrm{AlCl}}_3$. [1 Mark]