Which of the following statement about Hydrogen bonds is correct?

Question

BlackTom AI · Accepted Answer

Hydrogen bonding arises when a hydrogen atom covalently bonded to a highly electronegative atom (typically F, O, or N) interacts attractively with a lone pair on another electronegative atom.

1) Relevant knowledge points and concepts
- A hydrogen bond is an intermolecular (or intramolecular) attractive interaction caused by the polarity of an X–H bond (X = F, O, N). The electronegative X pulls electron density away from H, giving H a partial positive charge (δ+).  
- A hydrogen-bond donor is the X–H group; a hydrogen-bond acceptor is an electronegative atom with a lone pair. Both donor and acceptor are required for a hydrogen bond.  
- Hydrogen bonding is directional and significantly influences physical properties (e.g., high boiling point of water, ice’s open lattice).

2) Step-by-step reasoning
- Identify the donor: X–H where X is electronegative → creates Hδ+.  
- Identify the acceptor: another electronegative atom with a lone pair.  
- The electrostatic attraction between Hδ+ and the lone pair constitutes the hydrogen bond; because it arises from uneven electron distribution, it is a polar interaction.

3) Intermediate conceptual steps
- Electronegativity difference → partial charges (δ+ on H) → electrostatic attraction to lone pair → hydrogen bond formed.  
- Example: In water, O–H (donor) interacts with O lone pair (acceptor) on a neighboring molecule; this network explains water’s anomalous properties.

4) Why the correct answer is correct
- Option (a) states that a hydrogen bond is a polar bond formed when a hydrogen atom is shared between two electronegative atoms. This captures the essence: H is polarized by one electronegative atom and interacts with another electronegative atom (the “sharing” is an electrostatic interaction), so (a) is accurate.

5) Why other options are incorrect
- (b) “only requires a H-bond (e.g. OH, NH)” is incomplete: a donor alone is insufficient; an acceptor is also required.  
- (c) is false: water’s structure and behavior depend strongly on hydrogen bonding.  
- (d) “only requires a H-bond acceptor” is likewise incomplete; a donor is also necessary.

Conclusion: Therefore the correct choice is (a), matching the provided answer.

Which of the following statement about Hydrogen bonds is correct?单项选择题

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