The student clearly identified the independent variable (the concentration of sodium sulfate) and the dependent variable (the solubility of calcium sulfate), demonstrating a solid understanding of their relationship. The research question effectively outlined the analytical method of complexometric titration with EDTA, providing clarity on how the solubility would be determined. Additionally, the student provided a comprehensive theoretical background on the common ion effect, explaining its relevance to the investigation and supporting it with appropriate calculations. The methodology was well-detailed, allowing for reproducibility, and the student addressed controlled variables and safety considerations appropriately. However, the student did not sufficiently discuss ethical and environmental issues related to the investigation, which would have enhanced the overall assessment.
