Alcohols, Aldehydes And Ketones Flashcards
What type of reaction produces and aldehyde or ketone ?
Oxidation Reaction
How can you prevent a carboxylic acids being formed instead of an aldehyde ?
Gentle warming and then distilled off to prevent carboxylic acid formation
Test for a carbonyl group (both aldehydes and ketones) and the Observation
Add 2,4-DNPH
Orange red ppt formed
It is then recrystallised to purify into the original aldehyde / ketone, identified by specific melting points
What are the 2 test to identify an aldehyde?
Tollens Reagent - produces silver mirror
Fehlings Reagent - blue to red ppt
Test to identify alkene and observation
Add bromine / bromine water
Orange to colourless
Test for primary and secondary alcohols and observations
Acidified potassium dichromate = orange to green
Acidified potassium manganate = purple to colourless
Test for carboxylic acid and observations
Add sodium hydrogen carbonate
CO2 bubbles produced
Test for a methylcarbonyl / methyl ketone group and observations
Triiodomethane test
Add iodine and sodium hydroxide
Yellow ppt formed from the CHI3 produced and a antiseptic smell
What reagent is used to reduced aldehydes and ketones into their original alcohols ?
Sodium tetrahydridoborate, NABH4, in aqueous solution
Describe the Nucleophilic addition of HCN
The CN group breaks the C=O bond and attaches itself to the carbon. The oxygen is left with a single bond and a lone pair of electrons. The lone pair of electrons is transferred to the Hydrogen to form an OH group
Hydroxynitirile produced
What reagent reduces a carboxylic acid into primary alcohol?
LiAlH4 - lithium tetrahydridoaluminate
What conditions are require to form an alcohol from a Halogenoalkane ?
Warm aqueous sodium or potassium hydroxide
What conditions are require to form an alcohol from a Halogenoalkane ?
Warm aqueous sodium or potassium hydroxide
Give reactants and conditions required for the formation of a hydroxynitrile from an aldehyde/ketone
Potassium or sodium cyanide is added to sulfuric acid to produce hydrogen cyanide
Temperature of 20c
Why is NaBH4 used for the reduction of aldehydes and ketones but not for carboxylic acids ?
It isn’t reactive enough to reduce carboxylic acids
What type of organic products is produced in the reaction between alcohols and hydrogen halides?
Halogenoalkane
What catalyst is required for the reaction of primary / secondary alcohols with hydrogen chloride?
Anhydrous zinc chloride
Name the type of mechanism between an alcohol and acyl chloride
Nucleophilic Addition elimation
What are the conditions and catalyst require for an esterification reaction ??
The alcohol and carboxylic acid must not heated in the presence of a strong acid catalyst e.g conc sulfuric acid
What is the colour change when ferric chloride is added to phenol?
Vivid-purple colour
What is the test for phenols ?
Add aqueous FeCl3 to test for the presence of phenols
Solutions will turn purple, blue, green or red colour depending on the nature of the phenol
What is the product formed when a phenol reacts with ethanoyl chloride?
Phenyl ethanoate
Considering the acidity of phenol, will it react with NaOH and Na2CO3?
Reacts with NaOH but doesn’t with Na2CO3, due to it only being weakly acidic
Why does phenol generally react more readily than benzene ?
Phenol contains a lone pair of electrons on the oxygen atom. This electron pair is delocalised into the ring structure. Increasing the electron density of the ring and therefore more susceptible to electrophilic attack
