The faint pink colour is very difficult to observe with respect to human eye when a ffa test is done with used oil. The procedure is also a tough method which explained:

1. take the amount of 28.2 gm of oil in one conical flask (cf)

2. take 50 ml drops of propanol into another conical flask and add 20drops of phenolphthalein indicator and neutralize with two drops of .1 N of NaOH and a faint pink colour observed

3. Add the mixed propanol into the oil and heat at 60-70 degree celcius but donot boil it and keep it warm so that you can easily touch the bottom of the conical flask.

4. Now titrate it against .1N NaOH , take reading until it appears again a faint pink colour that was observed and colour should persist upto 30 seconds .

Now when we shake the titrating Cf the colour of dotted pink disappears..till long no color appears and until a cloudy solution appears and then titrating so long the colours appear as cloudy faint pink .

some says that colours should be noted when the dotted colour persists for upto 15 secs. but I saw their way of shaking, is very slow and the colour doesn't resemble the overall solution's colour i.e. a dotted pink colour.

How colour change is to be noted down? What is the exact way to perform this test then? Anyone have video based on same above procedure? The test is done for many times with the multiple times used oil for changing ffa (based on oleic acid), but unfortunately the way of experiment fails.

please show me a proper video with same procedure and observance of colour, results .