Tests for Compounds Flashcards
Fehling’s Test
Mix Fehling’s A (Contains Cu2+) and Fehling’s B
Blue to brick red with aldehyde (forms Cu2O precipitate)
Tollen’s Reagent
Colourless solution forms silver mirror with aldehyde
NaBH4
Reduces aldehydes and ketones to alcohols
Test for nitrate (V)
Warm with NaOH and Devarda’s alloy - produces ammonia gas
Test for Ammonia Gas
Turns damp red litmus paper blue, choking smell, forms white fumes with HCl
Test for Ammonium Ions
Warm with NaOH, produces ammonia gas
Test for certain anions/cations
Add sodium hydroxide - forms a coloured precipitate
Test for Halides
Add silver nitrate - forms a coloured precipitate Silver chloride is white Silver bromide is cream Silver iodide is yellow --- Mix with ammonia Silver chloride dissolves in dilute Silver bromide dissolves in concentrated Silver iodide does not dissolve
Test for Pb 2+
Add potassium iodide - forms bright yellow precipitate
Test for Sulphate ions
Add barium chloride, forms white precipitate
Flame Test
Dip wire loop into conc HCl and burn then dip into sample and hold over blue bunsen flame Li + crimson Na + orange-yellow K + Lilac Ca 2+ Brick Red Ba 2+ Green Cu 2+ Blue-green
Test for carbonates
Add HCl, releases CO2 gas
Test for Carbon Dioxide
I hope we know by now that Co2 turns limewater cloudy when bubbled through
Test for saturation
Add aqueous bromine, orange solution turns colourless with unsaturated molecule
Test for primary/secondary alcohols
Add acidified potassium dichromate, colour change from orange to green
