PAG 5.3 oxidation of ethanol Flashcards
method for experiment 1 complete oxidation of ethanol
1) add 4g sodium dichromate-2-water to the round-bottomed flask using the funnel
2) add 20 cm3 of sulfuric acid into the round-bottomed flask
3) add a few anti-bumping granules and swirl the flask to dissolve the solid
4) cool the solution by swirling the flask in an ice water bath for 2-3 minutes until the solution is ice cold
5) carefully add 0.5 cm3 ethanol to the flask dropwise with swirling in the ice-water
6) continue swirling the mixture until you see a temperature rise
7) when maximum temperature has been reached repeat step 4-6 with a second 0.5 cm3 of ethanol
8) clamp the flask by the neck, position in heating apparatus and arrange the condenser above the flask in a reflux setup
9) turn on condenser flow
10) heat the reaction under reflux for about 20 mins
11) allow the apparatus to cool for 5 mins then rearrange in the distillation set up
12) dry the outside of the flask with a paper towel
13) heat the reaction mixture gently with a low blue bunsen burner flame until you have distilled 2-3 cm3 of clear colourless distillate
14) test with universal indicator solution, anhydrous sodium carbonate solid and a few drops of sulfuric acid and acidified potassium dichromate
why can you not shake ethanoic acid with water to purify it?
ethanoic acid is soluble in water due to the -OH group being able to form hydrogen bonds so it will not separate when shaken with water so impurities cannot be isolated and removed with a separating funnel
