Question

Given below are two statements: 
Statement I: All the pairs of molecules \((\mathrm{PbO}, \mathrm{PbO_2}); (\mathrm{SnO}, \mathrm{SnO_2})\) and \((\mathrm{GeO}, \mathrm{GeO_2})\) contain amphoteric oxides. 
Statement II: \(\mathrm{AlCl_3}, \mathrm{BH_3}, \mathrm{BeH_2}\) and \(\mathrm{NO_2}\) all have incomplete octet. 
In the light of the above statements, choose the correct option.

• A. Both Statement I and Statement II are correct
• B. Both Statement I and Statement II are incorrect
• C. Statement I is correct but Statement II is incorrect
• D. Statement I is incorrect but Statement II is correct

Hint:

Key points to remember:
Lower oxides of heavier group 14 elements are often amphoteric
Higher oxides tend to be acidic
Electron-deficient molecules violate the octet rule

Answer 1

The Correct Option is D

Let's analyze each statement given in the question: 

• Statement I: All the pairs of molecules \((\mathrm{PbO}, \mathrm{PbO_2}); (\mathrm{SnO}, \mathrm{SnO_2})\) and \((\mathrm{GeO}, \mathrm{GeO_2})\) contain amphoteric oxides.
  • Amphoteric oxides can react with both acids and bases to form salt and water. Hence, they have the ability to exhibit both acidic and basic properties.
  • \(\mathrm{PbO}\) and \(\mathrm{SnO}\) are indeed amphoteric. However, \(\mathrm{PB0_2}\) and \(\mathrm{SnO_2}\) are generally considered as more acidic oxides rather than amphoteric. Similarly, \(\mathrm{GeO}\) is basic, while \(\mathrm{GeO_2}\) is typically acidic.
  • Thus, the statement that all specified oxides in each pair are amphoteric is incorrect.
• Statement II: \(\mathrm{AlCl_3}, \mathrm{BH_3}, \mathrm{BeH_2}\) and \(\mathrm{NO_2}\) all have incomplete octet.
  • The term "incomplete octet" refers to molecules in which the central atom possesses fewer than eight electrons in its valence shell.
  • \(\mathrm{AlCl_3}\), \(\mathrm{BH_3}\), and \(\mathrm{BeH_2}\) are classic examples of compounds with an incomplete octet, as they have six, six, and four electrons respectively in their outermost shell.
  • \(\mathrm{NO_2}\) also manifests an odd number of valence electrons, leading to an incomplete octet for the nitrogen atom. Hence, \(\mathrm{NO_2}\) can be considered as having an incomplete octet as well.
  • Therefore, Statement II is correct.

Conclusion: Statement I is incorrect because not all mentioned oxides are amphoteric. On the other hand, Statement II is correct, as all the stipulated compounds possess an incomplete octet.

Thus, the correct answer is: Statement I is incorrect but Statement II is correct.