option D
Explanation- The correct increasing order of Lewis-acid strength of these halides is BI3>BBr3>BCl3>BF3.
This can be explained on the basis of tendency of halogen atom to back donate its lone pair of electrons to the empty p-orbital of B atom through pπ−pπ bonding. As this tenedency is higher in case of F (due to identical size of 2 p- orbitals of B and F) the electron deficiency of B decreases and thus BF3 behaves as weakest Lewis acid. As the size of halogen atom increases from Cl to I, the tendency for back donation decreases and consequently the electron deficiency of B increases and Lewis acid character increases accordingly from BF3 to BI3.
The correct increasing order of Lewis-acid strength of these halides is BBr3>BCl3>BF3
This can be explained on the basis of tendency of halogen atom to back donate its lone pair of electrons to the empty p-orbital of B atom through pπ−pπ bonding. As this tenedency is higher in case of F (due to identical size of 2 p- orbitals of B and F) the electron deficiency of B decreases and thus BF3 behaves as weakest Lewis acid. As the size of halogen atom increases from Cl to Br, the tendency for back donation decreases and consequently the electron deficiency of B increases and Lewis acid character increases accordingly from BF3 to BBr3.
So,option D is correct...stability of adduct increases with increases in lewis acid character of boron trihalides.
When the halide is more electronegative the interelectronic repulsion increases making the molecule difficult to accept a lone pair.
Size of halide also behaves in the same way. Also the degree of hydrolysis increases from fluorine to iodine,so the lewis acidic character increases in the same order. option B is correct.
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Dinesh khalmaniya 1 Best Answer
option D Explanation- The correct increasing order of Lewis-acid strength of these halides is BI3>BBr3>BCl3>BF3. This can be explained on the basis of tendency of halogen atom to back donate its lone pair of electrons to the empty p-orbital of B atom through pπ−pπ bonding. As this tenedency is higher in case of F (due to identical size of 2 p- orbitals of B and F) the electron deficiency of B decreases and thus BF3 behaves as weakest Lewis acid. As the size of halogen atom increases from Cl to I, the tendency for back donation decreases and consequently the electron deficiency of B increases and Lewis acid character increases accordingly from BF3 to BI3.
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