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STD 11 - 4. Chemical bonding and molecular structure — JEE STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceJEESTD 11 - 4. Chemical bonding and molecular structure4 Marks
MCQ
Assertion : $B_2$ molecule is diamagnetic.
Reason : The highest occupied molecular orbital is of $\sigma $ type.
  • A
    If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
  • B
    If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
  • C
    If the Assertion is correct but Reason is incorrect.
  • ✓
    If both the Assertion and Reason are incorrect.
✓

Answer

Correct option: D.
If both the Assertion and Reason are incorrect.
d
$B_2$ molecule has no of electrons $= 10$

Molecular orbital configuration
$\sigma {\left( {1s} \right)^2}\,{\sigma ^*}{\left( {1s} \right)^2}\,\sigma {\left( {2s} \right)^2}\,{\sigma ^*}{(2s)^2}\,\pi 2p_x^1\,\pi 2p_y^1$
Due to unpaired electron, it is paramagnetic. The highest occupied $MO$ is of $\pi -$ type.

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