Question

All members of group $14$ when heated in oxygen form oxides. Which of the following is the correct trend of oxides?

• A. Dioxides $C{O}_2,Si{O}_2$ and $Ge{O}_2$ are acidic while $Sn{O}_2$ and $Pb{O}_2$ are amphoteric
• B. $CO,GeO,SnO$ and $PbO$ are amphoteric
• C. Monoxides react with haemoglobin to form toxic compounds
• D. All oxides burn with blue flame

Answer 1

Answer: (A)

Being acidic $C{O}_2,Si{O}_2$ and $Ge{O}_2$ react only with bases.
$\underset{\text{acid}}{C{O}_2}+\underset{\text{base}}{2NaOH}⟶\underset{\text{salt}}{N{a}_{2}C{O}_3}+H_{2}O$
$\underset{\text{acid}}{Si{O}_2}+\underset{\text{ base }}{2NaOH}⟶\underset{\text{salt}}{N{a}_{2}Si{O}_3}+H_{2}O$
$\underset{\text{acid}}{Ge{O}_2}+\underset{\text{base}}{2NaOH}⟶\underset{\text{salt}}{N{a}_{2}Ge{O}_3}+H_{2}O$
$Sn{O}_2$ and $Pb{O}_2$ react with both acids and bases. Thus, amphoteric in nature.
$\underset{\text{acid}}{Sn{O}_2}+\underset{\text{base}}{2NaOH}⟶\underset{\text{salt}}{N{a}_{2}Sn{O}_3}+H_{2}O$
$\underset{\text{base}}{Sn{O}_2}+\underset{\text{acid}}{4HCl}⟶\underset{\text{salt}}{SnC{l}_4}+2H_{2}O$
$\underset{\text{acid}}{Pb{O}_2}+\underset{\text{base}}{2NaOH}⟶\underset{\text{salt}}{N{a}_{2}Pb{O}_3}+H_{2}O$
$\underset{\text{base}}{Pb{O}_2}+\underset{\text{acid}}{4HCl}⟶\underset{\text{salt}}{PbC{l}_4}+2H_{2}O$
Hence, dioxides $C{O}_2,Si{O}_2$, and $Ge{O}_2$ are acidic while $Sn{O}_2$ and $Pb{O}_2$ are amphoteric.