Evaluation of the time-dependent chemical alterations in sodium hypochlorite solution waited during the treatment period

This thesis aims to evaluate the effect of keeping sodium hypochlorite (NaOCl) solution in open containers for different periods on pH, active chlorine content, and surface tension values. For each group, 20 ml of fresh NaOCl was put into ten open, transparent containers. In Group 1 (control group), pH, active chlorine content, and surface tension values were measured immediately without keeping the solution open. In the second and third groups, the same measurements were made after keeping the NaOCl solutions open for 1 and 2 hours, respectively. In all groups, a digital pH meter was used for pH measurements, a Traube stalagmometer was used for surface tension measurements, and iodometric titration was used to determine active chlorine contents. One-way analysis of variance (ANOVA) and Duncan tests were used to analyze the data statistically. A statistically significant difference was found between the pH values of the solutions (p0.05). The pH values of the solutions kept for one and two hours were found to be significantly lower than those of the fresh solution. Again, it was determined that the pH of the solution kept for two hours decreased significantly compared to the one kept for one hour (p0.05). No statistically significant difference was found between the groups regarding surface tension values (p0.05). When the groups were evaluated in terms of active chlorine amounts, no difference was found between the fresh samples and the samples kept for one hour (p0.05), while the amount of active chlorine in the samples kept for two hours was found to be significantly higher than both the fresh and one-hour samples (p0.05). In this study conditions, it was concluded that as the waiting time of the NaOCl solution increased, the pH value decreased, the amount of active chlorine increased, and the surface tension did not change. Keywords: Active chlorine, Iodometric titration, pH, Sodium hypochlorite, Surface tension, Traube stalogmometer