Question

${\text{Si}}{{\text{O}}_{\text{2}}}$,${\text{Ge}}{{\text{O}}_{\text{2}}}$, ${\text{SnO}}$and ${\text{PbO}}$are respectively:
A. acidic, amphoteric, acidic, basic
B. basic, amphoteric, amphoteric, acidic
C. acidic, basic, amphoteric, basic
D. acidic, amphoteric, amphoteric, basic

Answer 1

Hint: To determine the answer of this question we should know what is acidic, basic and amphoteric oxides are. The nature of the oxide is decided based on its reaction. Metallic oxides behave as a base. Non-metallic oxides behave as acid. Amphoteric oxides behave as acid as well as a base.

 Complete step by step answer:Metallic oxides and hydroxide have metals and non-metallic oxides have non-metal.
The metal oxide on dissolving in water produces base. The non-metal oxide on dissolving in water produces acid.

The metal oxide reacts with acid so, they are base. The non-metal reacts with base so, they are acid.

So, the nature of metallic oxides is basic and the nature of non-metallic oxides is acidic.

Some metallic oxides react with base and acid both are known as amphoteric oxides.
The reaction of each oxide is as follows:
The reaction of silicon oxide with water is as follows:
${\text{Si}}{{\text{O}}_{\text{2}}}\,{\text{ + }}\,2\,{{\text{H}}_2}{\text{O}} \to \,{\text{Si}}{\left( {{\text{OH}}} \right)_4}$
The silicon is a non-metal and the product of the hydrolysis of silicon is a base so, the silicon oxide is acidic because it is reacting with a base.
${\text{Ge}}{{\text{O}}_{\text{2}}}$reacts with acid an base both so, it is an amphoteric oxide.
Tin oxide ${\text{Sn}}{{\text{O}}_2}$reacts with hydrochloric acid and sodium hydroxide both so, it is amphoteric.
${\text{Sn}}{{\text{O}}_2}\,{\text{ + }}\,{\text{HCl}} \to \,{{\text{H}}_{\text{2}}}{\text{SnC}}{{\text{l}}_{\text{6}}}\,{\text{ + }}\,{{\text{H}}_{\text{2}}}{\text{O}}$
${\text{Sn}}{{\text{O}}_2}\,\,{\text{ + }}\,{\text{NaOH}} \to \,{\text{NaSn}}{{\text{O}}_3}\,{\text{ + }}\,{{\text{H}}_{\text{2}}}{\text{O}}$
Lead oxide ${\text{PbO}}$reacts with hydrochloric acid and give lead chloride.
${\text{PbO}}\,{\text{ + }}\,{\text{HCl}} \to \,{\text{PbC}}{{\text{l}}_2}\,{\text{ + }}\,{{\text{H}}_{\text{2}}}{\text{O}}$
${\text{Pb}}{{\text{O}}_2}$reacts with hydrochloric acid so, it is basic.
So, ${\text{Si}}{{\text{O}}_{\text{2}}}$,${\text{Ge}}{{\text{O}}_{\text{2}}}$, ${\text{SnO}}$and ${\text{PbO}}$are acidic, amphoteric, amphoteric, basic respectively.

Therefore, option (D) acidic, amphoteric, amphoteric, basic, is correct.

Note:Amphoterism depends upon the oxidation state of the metal. As the oxidation state increases the amphoterism increases. Because of increasing positive charge the polarising power of the metal increases. The non-metal oxides are acidic because they react with base. The metallic oxides are basic because they react with acid. Amphoteric oxides are both acidic as well as basic. Here, all oxides are of group-$14$. On going down in a group basicity increases. So, silicon forms acidic oxide and lead form basic oxide. Germanium and tin both lie in between the groups, so they form amphoteric oxide.