JEE MainChemistryp Block Elements (Group 13 & 14)
Given below are two statements: Statement I : Down Group 13, the nature of oxides changes from acidic to basic, with B ₂ O ₃ being acidic, Al ₂ O ₃ and Ga ₂ O ₃ being amphoteric, and In ₂ O ₃ and Tl ₂ O ₃ being basic. Statement II : The Lewis acid strength of boron trihalides follows the order BF ₃ > BCl ₃ > BBr ₃ > BI ₃ due to the high electronegativity of fluorine. In the light of the above statements, choose the c
Options
- ABoth Statement I and Statement II are true
- BStatement I is true but Statement II is false
- CBoth Statement I and Statement II are false
- DStatement I is false but Statement II is true
Correct answer
B. Statement I is true but Statement II is false
Step-by-step solution
Statement I is true. Down Group 13, metallic character increases, leading to a transition from acidic to basic oxides. B ₂ O ₃ is acidic, Al ₂ O ₃ and Ga ₂ O ₃ are amphoteric, while In ₂ O ₃ and Tl ₂ O ₃ are basic. Statement II is false. The correct order of Lewis acidic strength is BI ₃ > BBr ₃ > BCl ₃ > BF ₃ . In BF ₃ , strong p -p back-bonding occurs between the filled 2p orbital of fluorine and the vacant 2p orbital of boron. This partially satisfies the electron deficiency of boron, making BF ₃ the weakest Lew