Y12 Test Tube Tests Flashcards
How do you test for an alkene?
Bromine water
What is observed when an alkene is added to bromine water?
The Bromine water changes from orange to colourless.
Why does an alkene decolourise bromine water?
It reacts by electrophilic addition
What does sodium carbonate test for?
Inorganic
Acids
What is observed when sodium carbonate is added to an acid?
Effervescence (CO2 gas is released)
What is observed when acidified potassium dichromate is added to a primary alcohol?
The dichromate is reduced changing from orange to green
What is observed when acidified potassium dichromate is added to a secondary alcohol?
The dichromate is reduced changing from orange to green
What is observed when acidified potassium dichromate is added to an aldehyde?
The dichromate is reduced changing from orange to green
What is observed when acidified potassium dichromate is added to a tertiary alcohol?
No change (tertiary alcohols can not be oxidised)
What is observed when acidified potassium dichromate is added to a ketone?
No change (ketones can not be oxidised by potassium dichromate)
What is observed when acidified potassium dichromate is added to a carboxylic acid?
No change (carboxylic acids can not be oxidised by potassium dichromate)
Tollen’s reagent is a test for which functional group?
Aldehyde
What is observed when Tollen’s reagent is added to an aldehyde?
A silver mirror forms
What happens to an aldehyde when it is tested using Tollen’s reagent?
the aldehyde is oxidised to a carboxylic acid
What is observed when Tollen’s reagent is added to a ketone?
No visible change
What reagent is used to test for ammounium ions?
Heat with NaOH
What is observed when ammounium (NH4+) ions are heated with NaOH
Gas released turns damp red litmus paper blue
What gas is released when ammonium ions are warmed with NaOH
ammonia gas (NH3)
What is Fehlings solution a test for?
Aldehydes
What is observed when an aldehyde reacts with Fehling’s solution?
Brick red precipitate
What reagent is used to test for sulfate ions (SO42-)?
Acidified BaCl2
What is observed when acidified BaCl2 is added to a solution containing sulfate ions (SO42-)?
White precipitate (BaSO4)
What is the ionic equation for the reaction of acidified BaCl2 with a solution containing sulfate ions (SO42-)?
Ba2+(aq) + SO42-(aq) → BaSO4(s)
What reagent is used to test for magnesium ions (Mg2+)?
NaOH
What is observed when NaOH is added to a solution containing Mg2+ ions?
White precipitate (Mg(OH)2)
What is the ionic equation for the reaction between NaOH and a solution containing Mg2+ ions?
Mg2+(aq) + 2OH-(aq) → Mg(OH)2(s)
What reagent is used to test for hydroxide ions?
Mg(NO3)2
What is observed when Mg(NO3)2 is added to a solution containing OH- ions?
White precipitate (Mg(OH)2)
What is the ionic equation for the reaction between Mg(NO3)2 and a solution containing OH- ions?
Mg2+(aq) + 2OH-(aq) → Mg(OH)2(s)
What reagent is used to test for carbonate ions (CO32-)?
Any acid. HNO3 is the safe choice of acid if in doubt
What would you expect to see when an acid is added to a solution containing carbonate ions (CO32-)?
Effervescence (CO2)
Write an ionic equation for the reaction between an acid and a solution containing carbonate ions (CO32-).
2H+ + CO32- → CO2 + H2O
