Question

Which of the following set of Oxides is not correctly matched?

• A. SnO, PbO - Neutral
• B. SnO$_2$, PbO$_2$ - Amphoteric
• C. SiO$_2$, GeO$_2$ - Acidic
• D. CO$_2$, GeO - Acidic

Hint:

Recall group 14 oxide trends: Top oxides (CO2, SiO2, GeO2) are acidic, monoxides like CO neutral, GeO acidic, SnO/PbO amphoteric. Use reactions with acids/bases to classify. Refer to NCERT for exam standards.

Answer 1

The Correct Option is A

1. In group 14, the nature of oxides changes down the group, with acidity decreasing and basicity increasing.
2. Option (1): SnO and PbO are amphoteric oxides, meaning they can react with both acids and bases. For example, SnO + 2HCl → SnCl$_2$ + H$_2$O (acidic) and SnO + 2NaOH → Na$_2$SnO$_2$ + H$_2$O (basic). Similarly for PbO. They are not neutral, so this set is incorrectly matched.
3. Option (2): SnO$_2$ and PbO$_2$ are amphoteric, reacting with acids (e.g., SnO$_2$ + 4HCl → SnCl$_4$ + 2H$_2$O) and bases (e.g., SnO$_2$ + 2NaOH → Na$_2$SnO$_3$ + H$_2$O), correct.
4. Option (3): SiO$_2$ and GeO$_2$ are acidic oxides. SiO$_2$ reacts with bases to form silicates (SiO$_2$ + 2NaOH → Na$_2$SiO$_3$ + H$_2$O), and GeO$_2$ is similar, correct according to standard classifications.
5. Option (4): CO$_2$ is acidic (forms carbonic acid with water), and GeO is acidic (behaves like an acidic oxide), correct.
6. Therefore, the set not correctly matched is (1) SnO, PbO - Neutral.