The hydrogen bonds in water are stronger than those in ammonia because:

• A. hydrogen bonds in ammonia are covalent, while those in water are ionic
• B. oxygen is more electronegative than nitrogen, leading to more polar O–H bonds in water
• C. water molecules are larger than ammonia molecules
• D. ammonia forms more hydrogen bonds per molecule than water

Answer: (B)

Verified step by step guidance

1. Understand the concept of hydrogen bonding: Hydrogen bonds are weak interactions that occur between a hydrogen atom covalently bonded to an electronegative atom (like oxygen or nitrogen) and another electronegative atom. These bonds are not ionic or covalent but are intermolecular forces.
2. Compare the electronegativity of oxygen and nitrogen: Oxygen is more electronegative than nitrogen, meaning it has a stronger ability to attract electrons. This results in more polar O–H bonds in water compared to N–H bonds in ammonia.
3. Analyze the polarity of the bonds: The higher polarity of O–H bonds in water leads to stronger partial charges on the hydrogen and oxygen atoms, which enhances the strength of hydrogen bonding between water molecules.
4. Consider molecular size and hydrogen bond formation: While water molecules are slightly larger than ammonia molecules, this does not directly affect the strength of hydrogen bonds. Additionally, ammonia forms fewer hydrogen bonds per molecule compared to water, which is not relevant to the strength of individual bonds.
5. Conclude the reasoning: The stronger hydrogen bonds in water are primarily due to the higher electronegativity of oxygen compared to nitrogen, which leads to more polar O–H bonds and stronger intermolecular interactions.