Question

Which is not correct? (1) $\mathrm{Ge}(\mathrm{OH}{)}_2$ is amphoteric. (2) ${\mathrm{GeCl}}_2$ is more stable than ${\mathrm{GeCl}}_4$. (3) ${\mathrm{GeO}}_2$ is less acidic than ${\mathrm{SiO}}_2$. (4) ${\mathrm{GeCl}}_4$ in $\mathrm{HCl}$ forms ${\left[{\mathrm{GeCl}}_6\right]}^{2-}$.

Short answer

Option 2 is incorrect.

Step-by-step solution

Analyze Option 1

Check if ${\text{Ge(OH)}}_2$ is amphoteric. An amphoteric substance can act both as an acid and as a base. Since ${\text{Ge(OH)}}_2$ can exhibit this behavior, it can be classified as amphoteric. Therefore, this option is correct.

Analyze Option 2

Verify the stability of ${\text{GeCl}}_2$ compared to ${\text{GeCl}}_4$. Generally, ${\text{GeCl}}_4$ is more stable due to its complete octet configuration around germanium. Hence, this option is incorrect.

Analyze Option 3

Evaluate the acidity of ${\text{GeO}}_2$ compared to ${\text{SiO}}_2$. ${\text{GeO}}_2$ is indeed less acidic than ${\text{SiO}}_2$, confirming this option as correct.

Analyze Option 4

Check the formation of ${\text{[GeCl}}_6{]}^{2-}$ in presence of $\text{HCl}$. ${\text{GeCl}}_4$ does form the anionic complex ${\text{[GeCl}}_6{]}^{2-}$, making this option correct.

Key concepts

Amphoteric substances

Understanding amphoteric substances is key in inorganic chemistry. Amphoteric substances can act both as acids and bases. This dual behavior allows them to neutralize both acids and bases, making them unique.
For example, ${\text{Ge(OH)}}_2$ is amphoteric, meaning it can donate protons (acting as an acid) or accept protons (acting as a base) depending on the reacting substance.
Another common amphoteric substance is aluminum hydroxide ${\text{Al(OH)}}_3$.
Recognizing amphoteric substances helps in predicting reactions and understanding compound behavior in different environments.

Stability of compounds

The stability of compounds is vital in determining how they react and persist under different conditions. For instance, ${\text{GeCl}}_4$ is more stable than ${\text{GeCl}}_2$.
This is because ${\text{GeCl}}_4$ achieves a full octet, satisfying the octet rule, which makes it less reactive and more stable.
On the other hand, ${\text{GeCl}}_2$ does not have a complete octet, making it more reactive and less stable. This stability impacts how these compounds are used and handled in practical applications.

Acidity comparison

Comparing the acidity of compounds like ${\text{GeO}}_2$ and ${\text{SiO}}_2$ can be quite insightful.
Acidity is the ability of a substance to donate protons. ${\text{SiO}}_2$ (Silicon dioxide) is more acidic than ${\text{GeO}}_2$ (Germanium dioxide).
This happens because Silicon (Si) is smaller and more electronegative than Germanium (Ge), leading to a stronger attraction of electrons towards the oxygen in ${\text{SiO}}_2$.
This makes ${\text{SiO}}_2$ more likely to donate protons compared to ${\text{GeO}}_2$. Understanding these acidity trends aids in predicting reactions and compatibility between compounds.

Anionic complexes

Anionic complexes are negatively charged groups consisting of a central metal atom bonded to surrounding ligands.
For example, ${\text{GeCl}}_4$ in $\text{HCl}$ forms the anionic complex ${\text{[GeCl}}_6{]}^{2-}$.
This occurs because ${\text{GeCl}}_4$ reacts with additional chlorine ions (\text{Cl}^{-}) from hydrochloric acid (HCl), resulting in ${\text{[GeCl}}_6{]}^{2-}$.
Anionic complexes are crucial in various chemical processes and applications, including catalysis and the formation of more complex structures.