Question

What is the formula and valency of aluminate?

Answer 1

Hint: As we know that aluminate is an ionic compound which is made from one or more aluminum atoms and oxygen atoms. This ion can form complex compounds hence also found in many complex structures. So here we have to write down the formula of aluminate ions with its valency.

Complete answer:
Let us understand about aluminum and aluminate ions followed by their formulas and respective valencies as follows:-
-Aluminum: It is a chemical element which belongs to group 13 with the symbol Al and atomic number 13. It has a density lower compared to those of other common metals at approximately one third that of steel. It also has a great affinity towards oxygen and hence forms a protective layer of oxide on the surface when exposed to air.
-Aluminate ion: It is an anionic compound which is made from one or more aluminum atoms and oxygen atoms. This ion can form complex compounds hence also found in many complex structures. These are amphoteric in nature and can dissolve in bases as well as acids.
The most common formulas of aluminate ions are:$Al{{O}_{2}}^{-1}$, $Al{{O}_{4}}^{-5}$
The valencies of aluminate ions are calculated as follows:-
Oxidation state of Oxygen: -2
Oxidation state of Aluminum: +3
-$Al{{O}_{2}}^{-1}$: (+3) + 2(-2) = -1
Hence its valency is -1.
-$Al{{O}_{4}}^{-5}$: (+3) + 4(-2) = -5
Hence its valency is -5.

Note:
-Aluminates of sodium are used industrially in dyeing to form a mordant and its
hydrated forms are used in water purification, sizing of paper and in the manufacturing of zeolites, ceramics. It is also used as catalysts in the petrochemical industry.