Chemistry Tests A Level

Front 1

Alkenes C=C

Back 1

Bromine water will turn colourless, from brown, in the presence of the C=C double bond

Front 2

Chloroalkanes R-Cl

Back 2

1. Warm sample up with NaOH (this will hydrolyse the chloroalkane and produce Cl- ions)

2. Add nitric acid (this removes any impurities)

3. Add ammoniacal silver nitrate (Tollen’s reagent)

Result: white ppt of AgCl will form

Front 3

Bromoalkane R-Br

Back 3

1. Warm with NaOH (this will hydrolyse the bromoalkane to form Br- ions)

2. Add nitric acid (this will remove all impurities)

3. Add ammoniacal silver nitrate (Tollen’s reagent)

Result: a cream ppt of AgBr will form

Front 4

Iodoalkane R-I

Back 4

1. Warm with NaOH (to hydrolyse the iodoalkane and form I- ions)

2. Add nitric acid (to remove any impurities)

3. Add ammoniacal silver nitrate (Tollen’s reagent)

Result: a yellow ppt of AgI will form

Front 5

Alcohol R-OH

Back 5

Add K2Cr2O7 to the sample and warm it up.

If the mixture changes colours from orange to green, a primary or secondary alcohol is present and was oxidised.

Front 6

Aldehyde R-CHO

Back 6

Add Tollen’s reagent.

If a silver mirror forms then it is an aldehyde. If not, it’s a ketone.

Alternatively add Fehling’s solution and get a brick red ppt with an aldehyde.

Front 7

Carboxylic Acid R-COOH

Back 7

Add an aqueous solution of NaHCO3. Carbon dioxide gas is produced and bubbles are seen.

Front 8

Carbon dioxide CO2

Back 8

Bubble it through limewater, it will turn cloudy.