NCEA Level 3 Chemistry – Aqueous Chemistry (AS91393) Practice Exam

When neutral salts dissolve in water, they dissociate into their constituent ions, which typically do not interact significantly with the water to change the pH of the solution. This dissociation occurs because the ionic bonds in the salt are broken by the polar nature of water molecules, allowing the individual positively charged cations and negatively charged anions to separate and disperse throughout the solution.

In the case of neutral salts, such as sodium chloride (NaCl), the resulting ions (Na⁺ and Cl⁻) neither consume nor produce protons (H⁺) or hydroxide ions (OH⁻) in significant quantities, thus maintaining the same pH as that of pure water, which is generally neutral (around pH 7). As a result, the dissolution of these salts in water does not lead to any change in acidity or basicity.

Understanding this characteristic of neutral salts is fundamental in aqueous chemistry, particularly in analyzing the properties of solutions and their interactions. The other options suggest changes in pH or conductivity that do not occur for neutral salts, emphasizing the specific behavior of these substances in aqueous environments.