Thiosulfate
Thiosulfate - Related Videos
09:41
Concentration Dependence - Student Protocol
0 Views •
2020
Source: Smaa Koraym at Johns Hopkins University, MD, USA Concentration DependenceExpand In this experiment, you will combine varying concentrations of aqueous HCl and sodium thiosulfate to make solid sulfur, which rapidly gathers into opaque yellow particles at a certain sulfur concentration. Since the reaction solution starts clear and colorless, you can easily tell when it reaches that concentration. You'll use the same test tube and total volume each time, so it will take the same amount...
05:08
Concentration Dependence - Instructor Prep
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2020
Source: Smaa Koraym at Johns Hopkins University, MD, USA Preparation of SolutionsExpand Here, we show the preparation of solutions for 10 students working in pairs, with some excess. Please adjust quantities as needed. Put on a lab coat, splash-proof safety glasses, and nitrile gloves. Obtain a waste container for aqueous sodium thiosulfate in advance. Note: HCl is toxic and highly corrosive, and sodium thiosulfate is an irritant, so the solutions for this lab must be prepared in a...
09:38
Dissolved Oxygen in Surface Water
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2023
Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University Dissolved oxygen (DO) measurements calculate the amount of gaseous oxygen dissolved in surface water, which is important to all oxygen-breathing life in river ecosystems, including fish species preferred for human consumption (e.g. bluegill and bass), as well as decomposer species critical to the recycling of biogeochemical materials in the system. The oxygen dissolved in lakes, rivers, and oceans is crucial for the...
03:17
Cyanobacterial Culture Synchronization and DNA Compaction Driven by Light-Dark Cycles
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2025
Source: Murata, K. et. al., Visualization of DNA Compaction in Cyanobacteria by High-voltage Cryo-electron Tomography. J. Vis. Exp. (2018)This video demonstrates the synchronous cultivation of cyanobacteria under light-dark cycles to study circadian-regulated DNA compaction. Fluorescence microscopy reveals condensed DNA at defined time points, confirming cell cycle alignment across the population.
02:24
A New Chromogenic Medium for Rapid Detection of Vibrio Species
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2025
Source: Yeung, M., et al. Development of a More Sensitive and Specific Chromogenic Agar Medium for the Detection of Vibrio parahaemolyticus and Other Vibrio Species. J. Vis. Exp. (2016)This video demonstrates a culture-based method for identifying Vibrio species, highlighting chromogenic agar as a more accurate alternative to the commonly used thiosulfate-citrate-bile salts-sucrose or TCBS agar. Chromogenic agar provides superior differentiation of Vibrio strains by detecting species-specific...
FAQs
The key redox event is reduction of iodine to iodide. During that reaction, thiosulfate is oxidized to tetrathionate, giving a defined conversion between the iodine consumed and the sulfur oxyanion product formed. Because these reactants and products follow a predictable pattern, the reaction can serve as a quantitative chemical signal rather than merely demonstrating sulfur reactivity.
The terminal sulfur is central to the oxidation pathway that produces tetrathionate. When thiosulfate reduces iodine, its sulfur framework does not remain unchanged; sulfur transfer accompanies the electron-transfer reaction. This links the visible analytical reaction to a specific chemical product and helps explain why thiosulfate is valuable in controlled redox measurements.
Although the two oxyanions are structurally related, the additional terminal sulfur in thiosulfate gives it redox behavior that sulfate does not provide in the described reaction. Thiosulfate can reduce iodine and form tetrathionate, whereas its importance here comes from sulfur transfer as well as oxygen-containing sulfur structure. That distinction supports its analytical and practical uses.
An iodometric analysis uses the predictable reaction between iodine and thiosulfate as the measurement step. The thiosulfate reacts with iodine, reducing it to iodide, so the quantity required is linked to the iodine generated or consumed during analysis. This relationship allows oxidizing agents to be measured indirectly, including dissolved oxygen and chlorine.
Thiosulfate provides a consistent redox response to iodine, which allows iodometric titrations to convert the presence of an oxidizing substance into a measurable chemical relationship. In this context, dissolved oxygen and chlorine are not identified solely by observation; their amounts can be assessed through the iodine-thiosulfate reaction used in the analytical procedure.
Thiosulfate compounds serve as photographic fixing agents. Their importance in this application arises from the same chemically active sulfur system that makes thiosulfate useful in redox chemistry, although the practical purpose is photographic processing rather than measuring an oxidizing agent. This use illustrates how the compounds function beyond analytical titrations.
In water treatment, thiosulfate compounds are used as dechlorination chemicals. Their redox reactivity provides a way to address chlorine in treated water, complementing their analytical use in measuring chlorine through iodometric methods. This application connects the chemistry of sulfur transfer with an operational goal: reducing residual chlorine during water-treatment processes.