Strongest hydrogen bond is shown by?

(A) Water

(B) Ammonia

(C) Hydrogen fluoride

(D) Hydrogen sulfide

Types of bonds

• Ionic: formed by electron transfer (loss/gain).
• Covalent: formed by sharing electron pairs.
• Hydrogen bond (H-bond): an attractive interaction between a hydrogen atom covalently bonded to a highly electronegative atom and a lone pair on another electronegative atom.
• Van der Waals forces: weak intermolecular attractions (e.g., dipole–dipole, London dispersion).

Electronegativity (EN) basics

• EN = an atom’s tendency to attract shared electrons.
• Across a period: EN increases (effective nuclear charge rises; smaller atomic size).
• Down a group: EN decreases (more shells, larger size, greater shielding).
• On the Pauling scale, fluorine (F) has the highest EN.

Hydrogen bonding

• Strong H-bonding typically involves H–F, H–O, or H–N (the classic electronegative trio: F, O, N).
• The electronegative atom pulls electron density from H, creating δ+ on H and δ− on the acceptor, enabling a strong intermolecular attraction.

Which is strongest?

• Because F is the most electronegative, hydrogen fluoride (HF) forms the strongest hydrogen bonds among common hydrogen-bonding compounds (versus H₂O, NH₃, etc.).

Final: HF shows the strongest hydrogen bonding. (Therefore, option C.)