Group 7: Halogens
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- Hydrogen halides: audio tutorial
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- Are there any ways to analyse flourine concentrations in water in a class lab? 260308
- I have completed a titration for my chemistry investigation, "Determination of salt content in crisps". The titration was between a 0.02g dm-3 solution of sodium chloride with a 0.05 mol dm-3 silver nitrate solution. I have been told that this is the standardisation of silver nitrate. However, I am not sure of what this means and would like to know how it will help me with my next titration which is the same above except a "crisp solution" is used instead of a sodium chloride solution. 021108
- Hi. Currently I am working on a report of the experimental analysis of commercial bleaches using iodometric titrations, investigating the concentration of hypochlorite ions of two brands of bleaching solution respectively. Yet, I am really stuck in several aspects, and I hope you can answer these questions. 1. As the brown I2/I- solution becomes colourless at the end-point, why do we bother to add starch solution to indicate the end-point? 2. During the experiment, the sodium chlorate(I) should react with an excess of potassium iodide solution in the presence of acid. But the point is, the excess KI solution should be added before the acid. Why is this so? Is there any ground to justify this sequence of adding the chemicals? 3. As a matter of fact, after chlorate(I) ions have reacted with excess iodide ions and hydrogen ions, the I2 so formed will then readily dissolve in the remaining I- to give I3-. Then, during the titration, which species does S2O32- react with? Is I3- or I2 the genuine reactant? 141108
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updated: 12 May 2004
