organic analysis

Testing for alcohols

Acidified potassium dichromate

Turns from orange to green

Primary and secondary have same colour change

Fehlings solution

Oxidises aldehydes but not ketones

Add fehlings and warm

Aldehydes go from blue to brick red precipitate

Ketones remain blue

To make tollens reagent

Silver nitrate solution

Add few drops of sodium hydroxide- pale brown precipitate forms

Add few drops of dilute ammonia until precipitate redissolves

Tollens reagent

Add aldehydes/ketone and place in water bath

If aldehyde present- tollens reduces to silver mirror

Ketones have no silver precipitate

Test for Alkenes

Add bromine water add bung and shake

If Alkene is present a colourless solution forms

Test for carboxcylic acid

React acid with carbonate

Produces co2 when bubbled through limewater turns cloudy

Mass spectrometry

Used to find relative molecular mass

Infrared spectroscopy

Uses infrared radiation to increase vibrational energy of covalent bonds

Frequency depends on

Atoms on either side of bond

Position of bond in molecule

Fingerprint region

Identify specific molecules

Lies between 500 and 1500

Size and position of peaks is unique

Extra peaks .indicates impurities

Infrared radiation and greenhouse gas

Absorb radiation and re emit it back towards earth

Covalent bond absorbs radiation