The bonds in crystaline ammonium chloride are?

Analyze the question: We need to identify every type of bond present in crystalline ammonium chloride, NH₄Cl.

Concept: NH₄Cl is made of two ions, NH₄⁺ and Cl⁻, so the compound has bonds inside the ammonium ion and a bond between the ions.

Step-by-step solution:

1. Ionic bond: The NH₄⁺ cation and the Cl⁻ anion are held together in the crystal lattice by electrostatic attraction. This is an ionic bond.

2. Covalent bonds: In NH₄⁺, nitrogen shares electrons with hydrogen. Three N-H bonds form by ordinary sharing, with each atom contributing one electron. These are covalent bonds.

3. Dative (coordinate) bond: Nitrogen in NH₃ has a lone pair. It donates this pair to an H⁺ ion, which has no electrons, to form the fourth N-H bond. Here both electrons in the bond come from nitrogen alone, so it is a dative covalent bond.

NH₃ + H⁺ → NH₄⁺

So the crystal contains ionic, covalent and dative bonds.

Checking the options:

• A. Leaves out the ionic bond, which is wrong because NH₄⁺ and Cl⁻ are ions.
• B. Leaves out the dative bond, so it is incomplete.
• C. Ionic, covalent and dative. This is correct.
• D. Hydrogen bonds do exist between NH₄⁺ and Cl⁻ in some descriptions, but they are intermolecular attractions, not the primary bonds of the compound. The dative bond is the classic answer WASSCE expects.

Answer: C

Exam tip: Whenever you see NH₄⁺ (or H₃O⁺), think "dative bond." For NH₄Cl, remember the trio: ionic (between ions) + covalent (N-H) + dative (the fourth N-H).