paper 6 tests

Food test: starch

• Iodine: orange/brown -> blue black

• Benedict's: heat - light blue -> green/brick red

• Biuret: blue -> lilac purple

• Ethanol: shake - colourless -> cloudy/milky

Food test: reducing sugar

• Iodine: orange/brown -> blue black

• Benedict's: heat - light blue -> green/brick red

• Biuret: blue -> lilac purple

• Ethanol: shake - colourless -> cloudy/milky

Food test: lipid

• Benedict's: heat - light blue -> green/brick red

• Iodine: orange/brown -> blue black

• Biuret: blue -> lilac purple

• Ethanol: shake - colourless -> cloudy/milky

Food test: protein

• Ethanol: shake - colourless -> cloudy/milky

• Benedict's: heat - light blue -> green/brick red

• Biuret: blue -> lilac purple

• Iodine: orange/brown -> blue black

Tests for gases: ammonia (NH3)

• turns damp red litmus paper blue

• bleaches damp litmus paper

• relights a glowing splint

• 'pops' with a lighted splint

Tests for gases: chlorine (Cl2)

• turns red litmus paper blue

• 'pops' with a lighted splint

• relights a glowing splint

• bleaches damp litmus paper

Tests for gases: hydrogen (H2)

• turns lime water milky

• bleaches damp litmus paper

• relights a glowing splint

• 'pops' with a lighted splint

Tests for gases: oxygen (O2)

• 'pops' with a lighted splint

• turns damp litmus paper blue

• relights a glowing splint

• turns lime water milky

Tests for anions: carbonate (CO3 2-)

• acidify, then add aqueous barium nitrate

  -> white precipitate

• add aqueous sodium hydroxide, then aluminium foil; warm carefully

  -> ammonia produced

• add dilute acid

  -> effervescene, carbon dioxide produced

• acidify with dilute nitric acid, then add aqueous silver nitrate

  -> white precipitate

Tests for anions: chloride (Cl-)

• acidify with dilute nitric acid, then add aqueous silver nitrate

  -> white precipitate

• add dilute acid

  -> effervescence, carbon dioxide produced

• add aqueous sodium hydroxide, then aluminium foil; warm carefully

  -> ammonia produced

• acidify, then add aqueous barium nitrate

  -> white precipitate