Question

Briefly explain why water (H 2O) is an excellent solvent for NaCl. That is, why does NaCl dissolve in water?

Answer 1

Water consists of two hydrogen atoms attached to oxygen atom via covalent bonds. However, as oxygen is more electronegative than hydrogen, it attracts a shared electron pair resulting in the formation of a partially positive charge on hydrogen atoms and partially negative charge on the oxygen atom. As a result, a water molecule is a polar compound containing positive and negative charges. As sodium chloride is salt consisting of positively charged sodium cation and negatively charged chloride anion, Na⁺ and Cl^- ions tend to interact with polar water molecules via multiple electrostatic interactions. As a result, polar water molecules cover sodium and chloride ions providing the dissociation of NaCl and its dissolution in water.