Final answer:
Adding a substance that releases more hydronium ions than hydroxide ions to pure water results in the solution becoming acidic due to the imbalance in ion concentration.
Step-by-step explanation:
When adding a substance to pure water that releases more hydronium molecules than hydroxide, the solution is now considered to be acidic. In pure water, hydronium and hydroxide ions are present in equal concentrations, making the solution neutral. However, when an acid is added, the balance shifts, leading to a greater concentration of hydronium ions compared to hydroxide ions. Through this process, according to the Le Châtelier's principle, the solution becomes acidic because the increase in hydronium ions leads to an increase in the overall acidity of the solution.