Rp 06- Organic Tests

Question 1

How do you test for an alcohol?

Answer 1

• add 1cm3 of alcohol to a test tube, add a small piece of sodium
• presence of alcohol is indicated by white precipitate and effervescence

Question 2

How do you distinguish between different alcohol types ?

Answer 2

• heat under reflux with acidified potassium dichromate (VI)
• primary and secondary alcohols will be oxidised, shown by colour change, orange to green
• tertiary alcohols cannot be oxidised and will remain orange

Question 3

How do you test for an aldehyde?

Answer 3

• add fehlings solution to sample
• brick red ppt will form

Question 4

How do you test for an Alkene?

Answer 4

• add bromine water to sample and shake
• alkenes will decolorise bromine water

Question 5

How do you test for a Carboxylic acid?

Answer 5

• add sodium hydrogen carbonate to sample
• is carboxylic is present CO2 is given off

Question 6

How do you test for haloalkanes?

Answer 6

• add 5 drops of halo-alkane to 1cm3 of NaOH solution in a test tube
• warm contents of test tube at 60 degrees for a few minutes
• then add 2cm3 of dilute nitric acid and 1cm3 of silver nitrate solution
• if haloalkane is present, a precipitate should form. The colour of the ppt formed depends on the halide ions present in solution.

Question 7

What are the results of that test?

Answer 7

• white = chloride ions
• cream = bromide ions
• yellow = iodide ions