Q18 / 180 · COMEDK 2023 (Morning Shift) · Chemistry
Pick up the correct statement.
- AIn $\mathrm{BF}_3$ bond dicopoles are zero but dipole moment is higher.
- B$\mathrm{O}_2, \mathrm{H}_2$ shown bond diapole due to polarisation.
- Correct answerCDipole moment of ammonia is due to orbital dipole and resultant dipole in same direction.
- DDipole moment is scalar quantity.
Solution
The dipole moment of a molecule is a vector quantity, as it has both magnitude and direction. Thus, option (riUg0) is incorrect.
In $\mathrm{BF}_3$, the molecule has a trigonal planar geometry. The individual $\mathrm{B-F}$ bonds are polar, but the resultant dipole moment is zero due to the symmetry of the molecule. Thus, option (HcGbv) is incorrect.
$\mathrm{O}_2$ and $\mathrm{H}_2$ are homonuclear diatomic molecules. The electronegativity difference between the atoms is zero, so there is no bond dipole moment. Thus, option (KcrsK) is incorrect.
In ammonia ($\mathrm{NH}_3$), the nitrogen atom has a lone pair of electrons. The dipole moment contribution from the lone pair (orbital dipole) and the resultant dipole moment of the three $\mathrm{N-H}$ bonds are in the same direction, which adds up to give a significant net dipole moment. Thus, option (qbbOO) is the correct statement.
Answer: Dipole moment of ammonia is due to orbital dipole and resultant dipole in same direction.
In $\mathrm{BF}_3$, the molecule has a trigonal planar geometry. The individual $\mathrm{B-F}$ bonds are polar, but the resultant dipole moment is zero due to the symmetry of the molecule. Thus, option (HcGbv) is incorrect.
$\mathrm{O}_2$ and $\mathrm{H}_2$ are homonuclear diatomic molecules. The electronegativity difference between the atoms is zero, so there is no bond dipole moment. Thus, option (KcrsK) is incorrect.
In ammonia ($\mathrm{NH}_3$), the nitrogen atom has a lone pair of electrons. The dipole moment contribution from the lone pair (orbital dipole) and the resultant dipole moment of the three $\mathrm{N-H}$ bonds are in the same direction, which adds up to give a significant net dipole moment. Thus, option (qbbOO) is the correct statement.
Answer: Dipole moment of ammonia is due to orbital dipole and resultant dipole in same direction.
Hence, the correct answer is option: 'C'.