Three separate experiments (I, II, III) each involve combining two colorless aqueous…
CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
Three separate experiments (I, II, III) each involve combining two colorless aqueous solutions of electrolytes at 25 °C. For each experiment, a final particulate-level snapshot is described. No additional species are present other than those listed.
Experiment I: The solution contains free Na⁺ ions, free NO₃⁻ ions, free H₃O⁺ ions, and free Cl⁻ ions in roughly equal total concentrations. No clusters or gaseous particles are present.
Experiment II: Numerous water molecules are present along with free Na⁺ ions and free Cl⁻ ions. No other ions, clusters, or gas particles are observed.
Experiment III: The solution contains free Na⁺ ions and free NO₃⁻ ions. Spherical clusters composed of alternating small green spheres labeled H₂O and small purple spheres labeled ClO₄⁻ are dispersed but remain in the liquid phase; no gaseous species are present.
Use the descriptions to answer the following.
(a) For each experiment (I–III), list all ionic species that remain free in solution and state whether any precipitate or gas is present.
(b) Identify which experiment most clearly demonstrates an acid–base neutralization process. Cite specific particulate evidence to support your choice.
(c) For the experiment identified in part (b), write the balanced net ionic equation representing the chemical change.
(d) Justify why spectator ions are omitted from the equation written in part (c) by relating your reasoning to the particulate description.