Daniels000
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An alloy of chromel containing Ni,Fe & Cr was analysed by a complexometric titration using EDTA as the titrant. The solution of the alloy was prepared by dissolving 0.7176g of alloy in HNO3 and then diluted to mark in 250cm³ volumetric flask. 50cm³ of this aliquot of the sample was treated with pyrophosphate to mark the iron and chromium. If this aliquot of the sample require 26.14cm³ of 0.058M EDTA to reach the end point with murexide as the indicator. In a second titration 50cm³ aliquot treated with hexamethylenetetraamine to mask chromium require 35.43cm³ of 0.058M EDTA to reach the end point. Finally, a third 50cm³ of aliquot was treated 50cm³ of 0.058M EDTA and back titrated with 6.21cm³ of 0.063M Cu²+ yo reach the end point with murexide indicator. Calculate the percentage of Nickel, Iron and chromium in the alloy
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David Getling
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(Original post by Daniels000)
An alloy of chromel containing Ni,Fe & Cr was analysed by a complexometric titration using EDTA as the titrant. The solution of the alloy was prepared by dissolving 0.7176g of alloy in HNO3 and then diluted to mark in 250cm³ volumetric flask. 50cm³ of this aliquot of the sample was treated with pyrophosphate to mark the iron and chromium. If this aliquot of the sample require 26.14cm³ of 0.058M EDTA to reach the end point with murexide as the indicator. In a second titration 50cm³ aliquot treated with hexamethylenetetraamine to mask chromium require 35.43cm³ of 0.058M EDTA to reach the end point. Finally, a third 50cm³ of aliquot was treated 50cm³ of 0.058M EDTA and back titrated with 6.21cm³ of 0.063M Cu²+ yo reach the end point with murexide indicator. Calculate the percentage of Nickel, Iron and chromium in the alloy
The first titration allows you to work out the nickle.
The second gives you the combined nickle and iron. But as you already now have the nickle you can work out the iron.
The third gives you all three, but you already now have the iron and nickle. So you can take these away to get the chromium.
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Deggs_14
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Damn is this first year undergraduate chemistry? That looks hard!
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