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Deduce the molecular shape of BrF_(3) on the basis of VSEPR theory. |
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Answer» Solution :No. of electrons in the valence SHELL of the central BR atom = 7. No. of electrons provided by three F atoms `= 3 xx 1 = 3`. Total no. of electrons around the central Br atom = 7 + 3 = 10. `therefore` Total no. of electron pairs around the central Br atom = 10/2 = 5. But the no. of bond pairs = 3 (`because` there are three Br-F bonds) `therefore` No. of lone pairs = 5 - 3 = 2. On the basis of VSEPR theory, a molecule with three bond pairs and two lone pairs must be T-shapped (i.e., distorted trigonal bipyramidal) as shown. The tow lone pairs will occupy equatorinal positions to minimze lone pair-lone pair REPULSIONS WHIC are much stronger than lone pair-bond pair and bond pair-bond pair repulsions. Further, the axial F atoms will be slightly bent towards the equatorial F atom to minimize the lone pair-bond pair repulsions. Therefore, the shape of `BrF_(3)` would be slightly bent T as shown in Figure 
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