WAEC Chemistry 2010 Paper

Concept:Ammonium chloride contains more than one type of chemical bond within its crystal structure.Explanation:The formula of ammonium chloride is $\mathrm{NH}_{4}\mathrm{Cl}$.It exists as ammonium ions, $\mathrm{NH}_{4}^{+}$, and chloride ions, $\mathrm{Cl}^{-}$.The oppositely charged ions are held by an ionic bond.Inside the $\mathrm{NH}_{4}^{+}$ ion, nitrogen and hydrogen atoms are joined by covalent bonds.Among the four $\mathrm{N}-\mathrm{H}$ bonds, one is a dative (coordinate covalent) bond.This dative bond forms because the lone pair on nitrogen is donated to a hydrogen ion.Hydrogen bonds are not present as primary bonds in ammonium chloride crystals.Therefore, the crystal contains ionic, covalent, and dative bonds.Answer:C. ionic, covalent, and dative