Identify the correct orders against the property mentioned
A. H₂O > NH₃ > CHCl₃ – dipole moment
B. XeF₄ > XeO₃ > XeF₂ – number of lone pairs on central atom
C. O–H > C–H > N–O – bond length
D. N₂ > O₂ > H₂ – bond enthalpy
Choose the correct answer from the options given below:

CONCEPT:

Dipole Moment, Lone Pairs, Bond Length, and Bond Enthalpy

• Dipole Moment: The dipole moment depends on the electronegativity difference between bonded atoms and the molecular geometry.
• Lone Pairs on the Central Atom: The number of lone pairs can be determined using the molecular structure and valence electrons of the central atom.
• Bond Length: Bond length is inversely proportional to bond strength and directly related to the size of the atoms involved in the bond.
• Bond Enthalpy: Bond enthalpy is the energy required to break a bond. Triple bonds are stronger than double bonds, which are stronger than single bonds.

EXPLANATION:

• H₂O > NH₃ > CHCl₃ – Dipole Moment
  • H₂O has the highest dipole moment due to its bent shape and high electronegativity difference.
  • NH₃ has a lower dipole moment than H₂O, as it is pyramidal and less polar.
  • CHCl₃ has the lowest dipole moment because its geometry partially cancels out dipoles.
  • This order is correct.
• XeF₄ > XeO₃ > XeF₂ – Number of Lone Pairs on Central Atom
  • XeF₄: Xenon has 4 bonds and 2 lone pairs.
  • XeO₃: Xenon has 3 bonds and 1 lone pair.
  • XeF₂: Xenon has 2 bonds and 3 lone pairs.
  • The correct order of lone pairs is XeF₂ > XeF₄ > XeO₃, so this option is incorrect.
• O–H > C–H > N–O – Bond Length
  • O–H has the shortest bond length due to high bond strength and small atomic size.
  • C–H is longer than O–H but shorter than N–O.
  • N–O has the longest bond length due to weaker bond strength and larger atomic size.
  • This order is correct.
• N₂ > O₂ > H₂ – Bond Enthalpy
  • N₂ has the highest bond enthalpy due to the strong triple bond.
  • O₂ has a lower bond enthalpy than N₂ due to its double bond.
  • H₂ has the lowest bond enthalpy due to its single bond.
  • This order is correct.

Therefore, the correct answer is A, D only.