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deviation. The post-lab exercises will guide you through these calculations. 3 Part II. Analysis of your Bleach Unknown
Once you have standardized your sodium thiosulfate solution you can move on to the
analysis of your bleach unknown. Plan a titration procedure that will allow you to
determine the mass percentage of sodium hypochlorite in a bleach sample.
• Your procedure should be fundamentally the same as for the standardization,
but hypochlorite will take the place of iodate in the reactions. The tips for the
standardization procedure also apply for your unknown analysis.
• Plan to use a little less than a gram of bleach unknown in each of your titrations.
Record the mass of bleach used for each trial to a thousandth of a gram.
If you use single gram samples of bleach you will be able to use the same
amounts of the other reagents that you used in the standardization.
• Add about 5 drops of the ammonium molybdate catalyst solution to the
hypochlorite-iodide reaction in order to speed it up.
• Report the strength of the bleach as the effective mass percentage of the bleach
that is sodium hypochlorite, NaClO, for each titration and then report the average
mass percentage of sodium hypochlori...
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- Spring '07