01sbrals
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Hi, I am stuck on a practical write up for the oxidation of ethanol (PAG 5.3).
In experiment 1 (complete oxidation of ethanol making ethanoic acid)
3CH3CH2OH +16H +Cr2O7 = 3CH3COOH + 11H2O + 4Cr
Uses 4g of sodium dichromate, 20cm3 of 3.0moldm-3 sulfuric acid and 0.5cm3 of ethanol.

In experiment 2 (partial oxidation of ethanol making ethanal)
3CH3CH2OH + 8H + Cr2O7 = 3CH3CHO + 7H2O + 2Cr
Uses 2g of sodium dichromate, 20cm3 of 2.0moldm-3 sulfuric acid and 0.5cm3 of ethanol.

The questions are:
1) Explain how the different quantities of Na2Cr2O7.2H2O and different reaction conditions allow different organic products to be formed. Density of ethanol= 0.78g cm-3

2) A common step in the purification of organic liquid products is shaking the water followed by separation using a separating funnel. Explain why this would not be appropriate for purifying ethanoic acid.

3) Write an equation for the reaction between ethanoic acid and sodium carbonate. Discuss how your results provide evidence for the higher acid strength of ethanoic acid compared with ethanal.

Any help would be really appreciated, thank you.
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charco
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(Original post by 01sbrals)
Hi, I am stuck on a practical write up for the oxidation of ethanol (PAG 5.3).
In experiment 1 (complete oxidation of ethanol making ethanoic acid)
3CH3CH2OH +16H +Cr2O7 = 3CH3COOH + 11H2O + 4Cr
Uses 4g of sodium dichromate, 20cm3 of 3.0moldm-3 sulfuric acid and 0.5cm3 of ethanol.

In experiment 2 (partial oxidation of ethanol making ethanal)
3CH3CH2OH + 8H + Cr2O7 = 3CH3CHO + 7H2O + 2Cr
Uses 2g of sodium dichromate, 20cm3 of 2.0moldm-3 sulfuric acid and 0.5cm3 of ethanol.

The questions are:
1) Explain how the different quantities of Na2Cr2O7.2H2O and different reaction conditions allow different organic products to be formed. Density of ethanol= 0.78g cm-3

2) A common step in the purification of organic liquid products is shaking the water followed by separation using a separating funnel. Explain why this would not be appropriate for purifying ethanoic acid.

3) Write an equation for the reaction between ethanoic acid and sodium carbonate. Discuss how your results provide evidence for the higher acid strength of ethanoic acid compared with ethanal.

Any help would be really appreciated, thank you.
You got no ideas?

(your equations are incorrect btw)
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01sbrals
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Those are the equations we were given. For question 1, I need to work out the moles of the oxidising agents but I don’t know how
(Original post by charco)
You got no ideas?

(your equations are incorrect btw)
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charco
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(Original post by 01sbrals)
Those are the equations we were given. For question 1, I need to work out the moles of the oxidising agents but I don’t know how
The oxidation takes place in two stages.

1. First the alcohol is oxidised to the aldehyde
2. Then the aldehyde is oxidised to the carboxylic acid

If there isn't enough reagent then stage 2 cannot happen.
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