8 RBTS PAPER
164446
The correct order of stability in decreasing manner:
1 \(\mathrm{AlF}_6^{-3}>\mathrm{AlCl}_6^{-3}>\mathrm{AlBr}_6^{-3}>\mathrm{AlI}_6^{-3}\)
2 \(\mathrm{AlF}_6^{-3}<\mathrm{AlCl}_6^{-3}<\mathrm{AlI}_6^{-3}<\mathrm{AlBr}_6^{-3}\)
3 \(\mathrm{AlF}_6{ }^{-3}<\mathrm{AlCl}_6^{-3}<\mathrm{AlBr}_6{ }^{-3}<\mathrm{AlI}_6^{-3}\)
4 \(\mathrm{AlI}_6^{-3}<\mathrm{AlBr}_6^{-3}<\mathrm{AlCl}_6^{-3}<\mathrm{AlF}_6^{-3}\)
Explanation:
As size of surrounding element decreases stearic rupulsion decrease so stability increase.