Question

We know that $A{l_2}{O_3}$ reacts with_____:
A.Only water
B.Only acids
C.Only alkalis
D.Both acids and alkalis

Answer 1

Hint:Amphoteric oxides are the oxides which can act either as base or as an acid in a reaction to produce salt and water. Amphoteric nature of chemical species depends on the oxidation states available to that chemical species.

Complete step by step answer:
On the basis of acid-base characteristics, oxides can be classified into following categories
Acidic Oxides: The oxides which combine with water to give an acid are referred to as acidic oxides. These are binary compounds formed by the binary compound formed by the combination of non-metals with oxygen. These are generally covalent in nature. Examples are $C{O_2}$ , $S{O_2}$
Basic Oxides: The oxides which combine with water to give a base are referred to as acidic oxides. These are formed by the combination of highly electropositive metals with oxygen and are generally ionic in nature. Examples $BaO,CaO,N{a_2}O$
Neutral Oxides: Neutral oxides show neither basic nor acidic properties and hence do not form salts when reacted with acids or bases. Examples of neutral oxides are carbon monoxide, nitrous oxide, nitric oxide
Amphoteric Oxides: The oxides which show both acidic and basic characteristics are called amphoteric oxides. These react with both acid and base to form salts and $A{l_2}{O_3}$ is an example of amphoteric oxide therefore $A{l_2}{O_3}$ reacts with both alkalis and acids hence option ‘D’ is the correct solution for the given question
The reaction of $A{l_2}{O_3}$ with acid and alkali is shown below as follow
$A{l_2}{O_3} + 6HCL \to 2AlC{l_3} + 3{H_2}$ (With acid)
$A{l_2}{O_3} + 2NaOH \to 2NaAl{O_2} + {H_2}O$ (With alkalis)
Hence option D is the correct answer.

Note:Further oxides can also be classified on the basis of oxidation number of oxygen as peroxides and superoxides. In peroxide oxygen exist in an oxidation state equal to $ - 1$ while in superoxides the oxygen has oxidation state $\dfrac{{ - 1}}{2}$