In the following sets of reactants which two sets best exhibit the amphoteric characters of $$A{l_2}{O_3}.\,x{H_2}O?$$
$$\eqalign{
& {\text{Set}}\,1{\text{:}}\,A{l_2}{O_3}.\,x{H_2}O\left( s \right)\,{\text{and}}\,O{H^ - }\left( {aq} \right) \cr
& {\text{Set}}\,{\text{2:}}\,A{l_2}{O_3}.\,x{H_2}O\left( s \right){\text{and}}\,{{\text{H}}_2}O\left( l \right) \cr
& {\text{Set}}\,{\text{3:}}\,A{l_2}{O_3}.\,x{H_2}O\left( s \right)\,{\text{and}}\,{H^ + }\left( {aq} \right) \cr
& {\text{Set}}\,{\text{4:}}\,A{l_2}{O_3}.\,x{H_2}O\left( s \right)\,{\text{and}}\,N{H_3}\left( {aq} \right) \cr} $$
A.
1 and 2
B.
1 and 3
C.
2 and 4
D.
3 and 4
Answer :
1 and 3
Solution :
Aluminium oxide is amphoteric oxide because it shows the properties of the both acidic and basic oxides. It reacts with both acids and bases to form salt and water.
$$\eqalign{
& A{l_2}{O_3}.\,x{H_2}O + 2NaOH \to NaAl{O_2} + {H_2}O \cr
& A{l_2}{O_3}.\,x{H_2}O + HCl \to AlC{l_3} + {H_2}O \cr} $$
Releted MCQ Question on Inorganic Chemistry >> P - Block Elements
Releted Question 1
The reddish brown coloured gas formed when nitric oxide is oxidised by air is