Hydrogen bonding in aqueous ammonium chloride

Steps:

• NH4Cl dissociates into NH4+ and Cl- ions in water.
• NH4+ features N-H bonds that act as hydrogen bond donors to water's oxygen.
• Cl- ions accept hydrogen bonds from water molecules via lone pairs.
• These interactions explain the ready dissolution and solution properties.

Why A is correct:

• Hydrogen bonding occurs when NH4+ donates from N-H to water's O-H, and Cl- accepts from water's H, as defined by intermolecular forces involving electronegative atoms.

Why the others are wrong:

• B: No chlorine odor; NH4Cl hydrolysis produces trace ammonia, not Cl2.
• C: Solution is acidic from NH4+ hydrolysis (NH4+ + H2O ⇌ NH3 + H3O+), not basic.
• D: NaOH + NH4Cl forms NH3 gas, which is basic and turns litmus blue, not red.

Final answer: A