9a

Question 1

bromine water test

Answer 1

Bromine water (Br2) is initially brown as a solution and when added to a solution with a double carbon bond the bromine will join onto this molecule as the carbon molecules want to make 4 bonds.This will cause the solution to turn colourless

Question 2

potassium permanganate

Answer 2

with a negative result:the solution stays purple because the molecules are saturated(all have single carbon bonds) and hence the potassium permanganate cannot join onto the molecule

with a positive result:unsaturated molecule present and hence the double bonds will break and the potassium permanganate will join onto the molecule turning colourless (hydroxyl groups added) with a brown precipitate(Manganese dioxide)

Question 3

the two tests for unsaturated molecules

Answer 3

bromine water test
potassium permangenate test

Question 4

hydroxyl group tests

Answer 4

Lucas test

acidified potassiumdichromate test

acidified potassium dichromate+silver mirror test

Question 5

acidified potassium dichromate test

Answer 5

presence of secondary and primary alcohols and results in the reduction of the Cr 6+ to Cr3+ and this causes colour change from orange to green

Question 6

silver mirror test purpose

Answer 6

differentiate between a primary secondary alcohol

Question 7

silver mirror test

Answer 7

to the solution of alcohol a Tollens reagent(ammoniacal silver nitrate solution)

positive= aldehyde present= partial oxidation=primary=silver look

negative=no silver look=ketone present

Question 8

Lucas test

Answer 8

test for presence of primary secondary and tertiary alcohol

Lucas Reagan