7+15- Tests For Organic + Inorganic

Question 1

Describe tests for Alkene

Answer 1

1- Add bromine water in fume cupboard

If present orange = colourless

Question 2

Test for Aldehyde - Tollens

Answer 2

1- Make Tollens reagent/ Ammonical silver nitrate
2- add silver nitrate + NaOH
3- dissolve precipitate formed by adding Ammonia solution
4- Add sample + Tollens/Ammoniacal silver nitrate

If present = silver mirror forms

Question 3

Test for Carboxylic acids

Answer 3

1- Add sample + Ethanol
2- add Sulphuric acid/H2SO4
3- heat mixture = Ester forms = fruity smell

Or

1- add sample + Carbonate
2- bubble gas produced through limewater

If present = CO2 turns limewater cloudy

Question 4

Describe a Flame test

Answer 4

1- Dip Nichrome wire into Conc HCl + place in roaring Bunsen to clean wire
2- Add metal + HCl to make “Slurry”
3- Dip wire into mixture/Slurry + put in flame

Question 5

Test for a Cation/ Positive Ion

Answer 5

1- Dissolve sample in distilled water
2- Add NaOH + Solution

If present a precipitate forms or a colour change

Question 6

Test for Halide Ions

Answer 6

1- Dissolve sample in distilled water
2- Add nitric acid
3- Add Silver Nitrate - AgNO3

If present coloured precipitate forms = can test further with Ammonia

Question 7

Test for sulphate ions

Answer 7

1- dissolve sample in distilled water
2- Add Dilute HCl followed by Barium Chloride
3- Record any colour change or precipitate formed

Question 8

Test for carbonate ions

Answer 8

1- Add Dilute HCl + sample
2- Bubble gas produced through limewater

CO2 turns limewater cloudy

*any acid + carbonate produces CO2