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JEE Main202127 Aug 2021Morning ShiftChemistryp Block Elements (Group 13 & 14)Actual

In which one of the following molecules strongest back donation of an electron pair from halide to boron is expected?

Options

  1. ABI 3
  2. BBBr 3
  3. CBCl 3
  4. DBF 3

Correct answer

D. BF 3

Step-by-step solution

Due to small size atom show strongest back bonding in BF 3 . In case of BF 3 ( 2 P - 2 P back bonding) while in BCl 3 ( 2 P - 3 P ) , BBr 3 ( 2 P - 4 P ) and BI 3 ( 2 P - 5 P ) back bonding. So extent of back bonding is maximum in 2 P - 2 P

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