Organics: Identification Tests Flashcards
What happens when red litmus paper is put in acid?
Stays red.
What happens when red litmus paper is put in a base?
Turns blue.
What happens when blue litmus paper is put in acid?
Turns red.
What happens when blue litmus paper is put in a base?
Stays blue.
What are the two main oxidising agents?
Acidified dichromate and acidified permanganate.
What is the colour change observed with acidified dichromate in an oxidation reaction?
orange to green
What is the colour change observed with acidified permanganate in an oxidation reaction?
purple to colourless
What happens when bromine water is added to an alkene?
Alkenes react rapidly via an addition reaction, bromine water turns from brown to clear.
What happens when bromine water is added to an alkane?
Alkanes only react with bromine water with addition UV light via substitution reaction, bromine water turns from brown to clear.
Describe benedicts and fehlings solution with aldehydes.
Oxidise aldehydes to carboxylic acids, turning Cu2+ solution from blue to a red-brown precipitate.
Describe benedicts and fehlings solution with ketones.
No reaction with ketones as no further oxidation can occur, solution stays blue.
Describe tollens reagent with aldehydes and ketones.
Reagent oxidises aldehydes but not ketones, Ag+ ions present cause silver mirror / black precipitate to form.
What is lucas’s reagent and what does it form?
ZnCl2/conc HCl and forms insoluble haloalkanes.
Describe lucas reagent with primary alcohol.
No colour change with primary alcohol because no insoluble haloalkanes will form.
Describe lucas reagent with secondary alcohol.
Cloudy after around ten minutes.
