Question

Given below are two statements:
Statement (I): \( \text{SiO}_2 \) and \( \text{GeO}_2 \) are acidic while \( \text{SnO} \) and \( \text{PbO} \) are amphoteric in nature.
Statement (II): Allotropic forms of carbon are due to property of catenation and \( p\pi-d\pi \) bond formation.
In the light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement I and Statement II are false
• B. Both Statement I and Statement II are true
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Answer 1

The Correct Option is C

To determine the validity of the given statements about chemical properties and allotropic forms, let's analyze each statement individually.

1. Statement I: \( \text{SiO}_2 \) and \( \text{GeO}_2 \) are acidic while \( \text{SnO} \) and \( \text{PbO} \) are amphoteric in nature.
   • \(<\text{SiO}_2\) is known to be an acidic oxide. It reacts with bases to form silicates. 
   • \(\text{GeO}_2\) also shows acidic properties, reacting with alkalis to form germanates.
   • \(\text{SnO}\) and \(\text{PbO}\) are amphoteric, meaning they can react with both acids and bases. For instance, \(\text{SnO}\) reacts with hydrochloric acid to form \(\text{SnCl}_2\) and with sodium hydroxide to form sodium stannate.
   • Thus, Statement I is accurate.
2. Statement II: Allotropic forms of carbon are due to the property of catenation and \( p\pi-d\pi \) bond formation.
   • Catenation is indeed a property of carbon that allows it to form multiple allotropes, such as diamond, graphite, and fullerenes, through chains or rings.
   • However, \( p\pi-d\pi \) bond formation is not typically associated with carbon allotropes. Carbon primarily forms \( p\pi-p\pi \) bonds.
   • Therefore, Statement II is incorrect.

Based on the analysis:

• Statement I is true: \( \text{SiO}_2 \) and \( \text{GeO}_2 \) are acidic, whereas \( \text{SnO} \) and \( \text{PbO} \) are amphoteric.
• Statement II is false: While catenation is a reason for carbon allotropy, the \( p\pi-d\pi \) bond formation is not a characteristic property of carbon for its allotropes.

Thus, the most appropriate answer is that Statement I is true but Statement II is false.

Answer 2

Statement (I):} This statement is correct. SiO$_2$ (silicon dioxide) and GeO$_2$ (germanium dioxide) exhibit acidic behavior as they are covalent oxides. On the other hand, SnO (tin(II) oxide) and PbO (lead(II) oxide) are amphoteric in nature, meaning they can react with both acids and bases.
Statement (II): This statement is false. While catenation is indeed a key property responsible for the existence of multiple allotropic forms of carbon, $\pi$-$\pi$ bond formation is not the primary reason for carbon allotropy. Instead, the different hybridization states (sp$^3$, sp$^2$, and sp) and bonding patterns play a more critical role.
Conclusion: Statement I is true as it accurately describes the nature of the oxides, while Statement II is false because it incorrectly attributes carbon allotropy primarily to $\pi$-$\pi$ bond formation.