Core Logic
Evaluating Statement I:
- SF₄$\mathrm{SF}_4$: sp³d$sp^3d$ (1 lone pair) arrow$\rightarrow$ See-saw
- XeF₄$\mathrm{XeF}_4$: sp³d²$sp^3d^2$ (2 lone pairs) arrow$\rightarrow$ Square planar
- [PtCl₄]²⁻$[\mathrm{PtCl}_4]^{2-}$: dsp²$dsp^2$ arrow$\rightarrow$ Square planar
- [NiCl₄]²⁻$[\mathrm{NiCl}_4]^{2-}$: sp³$sp^3$ arrow$\rightarrow$ Tetrahedral
- [Ni(CN)₄]²⁻$[\mathrm{Ni(CN)}_4]^{2-}$: dsp²$dsp^2$ arrow$\rightarrow$ Square planar
- SeF₄$\mathrm{SeF}_4$: sp³d$sp^3d$ (1 lone pair) arrow$\rightarrow$ See-saw
- NH₄^+$\mathrm{NH}_4^+$: sp³$sp^3$ (0 lone pairs) arrow$\rightarrow$ Tetrahedral
Total tetrahedral species = 2 ([NiCl₄]²⁻$[\mathrm{NiCl}_4]^{2-}$ and NH₄^+$\mathrm{NH}_4^+$). Statement I says 3, so it is false.
Evaluating Statement II:
- NO₂$NO_2$: Central N has 7 valence electrons (odd-electron molecule, incomplete octet).
- BeH₂$BeH_2$: Central Be has 4 electrons (incomplete octet).
- BF₃$BF_3$: Central B has 6 electrons (incomplete octet).
- AlCl₃$AlCl_3$ (monomer): Central Al has 6 electrons (incomplete octet).
Therefore, all molecules have incomplete octets. Statement II is true.
Step 1: Final Conclusion
Statement I is false, Statement II is true.
Chapter Mix
Class 11 Chemistry: Chemical Bonding and Molecular Structure
Class 12 Chemistry: Coordination Compounds