Chemistry - Tests

Name the reagent and observation to test for alkenes

R - Bromine water

O - orange → colourless

Name the reagent and observation to test for halogenoalkanes

R - add NaOH → warm →HNO₃ →AgNO₃

O -

AgCl = white precipitate

AgBr = cream precipitate

AgI = yellow precipitate

Name the reagent and observations to test for alcohols

R - acidified potassium dichromate

O -

Primary and secondary alcohols = orange → green

Tertiary alcohols = stays orange

Name the TWO reagents and observations to test for aldehydes

1R- Fehlings solution

1O- Solution turns from blue to red

2R- Tollens reagent

2O- Silver mirror forms

Name the reagent and observation to test for ketones

Fehlings and Tollens reagent

There will be no observable change

Name the reagent and observation to test for carboxylic acids

R- Add a carbonate (e.g: Na₂CO₃ or NaHCO₃

O- CO₂ released, turns limewater cloudy

Name the reagent and observation to test for carbonate ions

R- Dilute acid (e.g HCl)

O- effervescence, turns limewater cloudy

Name the reagent and observation to test for sulfate ions

R- Dilute HCl, then BaCl_{2 (aq)}

O- white pot of Barium sulfate forms

Name the reagent and observation to test for halide ions

R- dilute HNO₃, then AgNO₃

O-

Cl^-: white ppt, dissolves in dilute NH₃

Br^- : cream ppt, dissolves in concentrated NH₃

I^- : yellow ppt, insoluble in NH₃

Name the reagent and observation to test for ammonium ions

R- add aqueous NaOH, warm gently

O- Ammonia gas released, red litmus turns blue

Name the reagent and observation to test for hydroxide ions

R- Damp red litmus paper

O- red → blue

Name the TWO reagents and observations to test for Magnesium ions

1,

R- dilute NaOH

O- white ppt 

2,

R- dilute H₂SO₄

O- no visible change

Name the THREE reagents and observations to test for calcium ions

1, R- dilute NaOH O= slight white ppt

2, R - dilute H₂SO₄ O= slight white ppt

3, R - Flame test O= brick red

Name the THREE reagents and observations to test for Strontium ions

1, R= flame tests O= red

2, R= dilute NaOH O= no visible change

3, R= dilute H₂SO₄ O= white ppt