nashna
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A sample of solid ethanedioic acid (H2C2O4.2H2O) has been contaminated with potassium ethanedioate (K2C2O4.xH2O). A 1.780 g sample of this mixture was made up to a 250 cm3 solution with distilled water. A 25 cm3 sample was titrated against 0.100 mol dm-3 sodium hydroxide, requiring 17.35 cm3. Another 25 cm3 sample was acidified with sulphuric acid and titrated against 0.0200 mol dm-3 KMnO4 solution, requiring 24.85 cm3. Calculate x.
C2O42- → 2CO2 + 2e-
Any help would be much appreciated, thank you in advance
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TSR Jessica
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Sorry you've not had any responses about this. Are you sure you've posted in the right place? Here's a link to our subject forum which should help get you more responses if you post there.

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Just quoting in Puddles the Monkey so she can move the thread if needed
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charco
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(Original post by nashna)
A sample of solid ethanedioic acid (H2C2O4.2H2O) has been contaminated with potassium ethanedioate (K2C2O4.xH2O). A 1.780 g sample of this mixture was made up to a 250 cm3 solution with distilled water. A 25 cm3 sample was titrated against 0.100 mol dm-3 sodium hydroxide, requiring 17.35 cm3. Another 25 cm3 sample was acidified with sulphuric acid and titrated against 0.0200 mol dm-3 KMnO4 solution, requiring 24.85 cm3. Calculate x.
C2O42- → 2CO2 + 2e-
Any help would be much appreciated, thank you in advance
The first titration reacts with only the acid component of the mixture and the second titration reacts with the ethandioate ions in the mixture.

Moles of contaminant = moles of ethanoate - moles of acid/2

Convert moles to mass for both and then use ratios to find x
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