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In which one of the following molecules strongest back donation of an electron pair from halide to boron is expected ? (1) BCl3 (2) BF3 (3) BBr3 (4) BI3

1. BCl3
2. BF3
3. BBr3
4. BI3

Correct answer: BF3

Solution

BF3 is the correct option because the fluorine atom has a high electronegativity and can effectively donate its lone pair of electrons back to the electron-deficient boron, facilitating stronger back donation compared to the other halides.

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