analysis of inorganic and organic unknowns Flashcards
flame test
- clean the nichrome wire in concentrated hydrochloric acid and heat in bunsen burner
- dip the wire in powdered sample and put in flame and observe flame colour
testing for ammonium ions
- place 10 drops of ammonium chloride in a test tube
- add 10 drops of sodium hydroxide into the test tube and shake the mixture
- warm the mixture in a water bath
- test the fumes released with damp red litmus paper
- red litmus paper turns blue in the presence of ammonium ions
test for sulfate ions
barium chloride with hydrochloric acid is used as reagent to test or sulphate ions
with precipitate forms in the presence of sulfate ions
test for carbonate ions
add any dilute acid and observe effervescence
bubble gas through limewater to test for CO2 and limewater will turn cloudy
test for hydroxide ions
will turn red litmus paper blue
test for alkene
add bromine water and shake
alkenes decolourise the bromine water
test for alcohols and carboxylic acids
PCl5
result: misty fumes of HCl produced
test for alcohols, phenols, carboxylic acids
sodium metal
result: effervescence of hydrogen gas
test for carbonyls
2,4-DNP
result: orange or red crystals
test for aldehyde
fehling’s
result: blue solution to red precipitate
tollen’s
result: silver mirror formed
test for carboxylic acids
sodium carbonate
result: effervescence of carbon dioxide
test for primary and secondary alcohols
sodium dichromate and sulfuric acid
result: orange to green colour
test for acyl chloride
silver nitrate
result: vigorous reaction, steamy fumes of hydrochloric acid and rapid white precipitate of AgCl
iodoform test
iodine and sodium hydroxide
warm very gently
CHI3 formed which is a yellow crystalline with an antiseptic smell
