RP6

Question 1

How do you test for an alcohol?

Answer 1

● Add 1 cm3 of alcohol to a test tube, add a small piece of sodium.
● Presence of alcohol is indicated by a
white precipitate and effervescence.

Question 2

How do you distinguish between different alcohol types? (primary, secondary, tertiary etc.)

Answer 2

Heat under reflux with acidified potassium dichromate (VI). Primary and secondary alcohols will be oxidised- shown by a colour change from orange to green. Tertiary alcohols cannot be oxidised and will remain orange.

Question 3

How do you test for an aldehyde?

Answer 3

● Add Fehling’s solution to the sample. ● If an aldehyde is present, a red
precipitate will form.

Question 4

How do you test for an alkene?

Answer 4

● Add bromine water to the sample. ● If an alkene is present, the bromine
water will decolourise.

Question 5

How do you test for a carboxylic acid?

Answer 5

● Add Na2CO3 to the sample.
● If a carboxylic acid is present, CO2 will
be given off.

Question 6

How do you test for a haloalkane?

Answer 6

● Add 5 drops of haloalkane to about 1 cm3 of NaOH solution in a test tube.
● Warm the contents of the test tube at 60°C for a few minutes.
● Then add 2 cm3 of dilute nitric acid and 1 cm3 of silver nitrate
solution.
● If a haloalkane is present, a precipitate should form. The colour of
the precipitate formed depends on the halide ion present in
solution.
● White = Chloride ions, Cream = Bromide ions, Yellow = Iodide
ions.

Question 7

What are some common potential hazards and risks in the laboratory?

Answer 7

check