AQA 3.9 Carboxylic Acids and Derivatives REVISION

[@bhavanibhardwaj7464]

I am committed to taking the October chemistry A-level and proving the government wrong. These videos are literally saving me thank you so much. :)

[@AlleryChemistry]

You're welcome and good luck with your resit!

[@CertifiedYapping304]

how did they go? i hope it went well!

[@charlottem4733]

who disliked?? this video is great, thank you so much!

[@elaineistired4367]

42:31 the question says ‘ethanol’ but the mechanism shows methanol- just a heads up :)

[@tomekdavies9529]

Had to pick up the smallest little detail 😂

[@artemisstyx7145]

oh dam im glad u said cuz i sat there for 2mins questioning myself on ethanol and methanol

[@shannonharper2460]

Thank you so so much for doing this. As a mature student self teaching, these videos have been an invaluable resource.

[@AlleryChemistry]

You're very welcome!

[@嘉俊-v1s]

this really saves me. im suffering when i go through this topic

[@lucyr1450]

These videos are so amazing, they're so useful in recapping content and filling in gaps where teachers couldn't teach topics face to face due to covid, thank you!

[@comfychronicles]

Coweeeed

[@vinitakumar3827]

I'm doing a different exam board ccea which isn't really well known as its only in northern Ireland and I can say this video really reallly helped me understand this topic . Thank u so muchhhh

[@catherine4690]

For the Nucleophilic Addition-Elimination slide, the example says ethanol but the displayed formula for the alcohol is methanol... So for ethanol would the products be ethyl propanoate and HCl? Thank you :)

[@vanessayeung...]

not sure but i think it's ethyl ethanoate cuz the ester is CH₃CO₂CH₂CH₃, but yea + hcl

[@jjjssll]

Thank you so much sir, your hard work is greatly appreciated ❤

[@AlleryChemistry]

No problem 😊

[@kaviyam26]

Hi @Allery Chemistry. Thank you for this amazing job. Isn't basic hydrolysis of esters an irreversible reaction ? Please correct me if i'm wrong

[@jimliu7086]

I agree with you, is that right?

[@AS-mw6pw]

Do we need to memorise that making Aspirin equation? The spec just says we need to know the advantages of using ethanoic anhydride over ethanoyl chloride.

[@William.Hollier]

Brilliant

[@AlleryChemistry]

Thanks. Pleased you found it helpful!

[@cwacheats1234]

Who else is revising to do year 13 exams after September

[@nianicholson9070]

me!

[@rosefagan2847]

Thank you for another great video!☺

[@AlleryChemistry]

You're welcome 😊

[@lilypattison3026]

Hi there, on the Acyl Chloride Nucleophilic Addition-Elimination Reaction why does the reforming of the Oxygen double bond have the arrow pointing into the bond and not the Carbon? I thought it always had to point into the centre of an atom? Thank you so much for your help. You are a lifesaver

[@ajtrott1]

Hi lily. My understanding is at the start of mechanism, the very electron deficient (&+) carbon atom in COCl is highly susceptible to nucleophilic attack (nucleus loving), making acyl chlorides most reactive! - in this example, by methanol (he said ethanol in video but drew methanol by mistake i think). Since methanol acts as the nucleophile, the first step shows a curly arrow moving from one of the lone pairs on the electronegative oxygen atom in methanol towards the &+ charge on the electron deficient carbon atom of COCl group (arrow ALWAYS shows direction of electron movement for organic mechanisms), forming a new bond with acyl chloride molecule! But since first step is an addition reaction, the C atom in the acyl chloride now has one too many bonds! So the C=O bond in COCl group has to temporarily break and one of electron pairs in C=O double bond moves towards the electronegative (&-) oxygen atom (shown as curly arrow moving from C=O bond to O atom) forming C-O single bond now (so carbon again forms only 4 bonds) but leaving single negative charge on oxygen! Since this is a highly unstable molecule formed, the newly formed electron pair on O atom must immediately move back to reform the C=O bond - shown by curly arrow moving from lone pair on negative O atom back into C-O bond so reforming C=O again. Does this answer your initial question about why arrow moves back into the C=O bond? And not back towards the &+ C atom itself like in the initial nucleophilic addition step where new bond was formed with methanol (acting as nucleophile)? (In the final elimination step- To satisfy the C atom in acyl chloride part forming only 4 bonds again, the C-Cl bond breaks (heterolytically) instead of C=O again since chlorine atom is also electronegative (shown by curly arrow moving from electron pair in C-Cl bond onto Cl atom) forming a chloride ion Cl- (with extra lone pair of electrons). The Cl- ion then removes H atom from O-H bond in attached methanol ( with a curly arrow showing electron pair in O-H bond moving back onto O atom, thereby neutralising the temporary positive charge on O atom in methanol part). This is the final elimination step where hydrogen chloride is removed, leaving behind the newly formed ester! Ps This mechanism is much harder than a normal esterification reaction involving an alcohol and carboxylic acid (nucleophilic subsitution), as reaction between alcohol and acid chloride is two step (nucleophilic addition-elimination)! But don't worry this is the hardest mechanism you will come across in organic chemistry at A-level (to quote chris). I hope this helps! And hope Chris doesn't mind me answering your question - please feel free to add anything or correct if need be. As this is particularly challenging mechanism!

[@gianna3132]

Thank you for these! Super helpful:)

[@AlleryChemistry]

Glad you like them!

[@jaskamalsingh7839]

so cooked

[@greybands973]

im learning that now, you’ll be fine 😭

[@Gob_123]

I hate organic. Paper 2 will be my downfall.

[@infinitygaming6440]

same

[@fryhyh]

Its over for me

[@Charisse_]

In the base hydrolysis equation, no water was used on the hydroxide ions, why ?

[@vanessayeung...]

not sure but maybe cuz it broke O-H in NaOH. H then bond with RO to form an alcohol = ROH (?)

[@faithcarter8300]

I love your videos they are so good

[@chu2000]

for AQA do we need to know base hydrolysis mechanism

[@lareenahmad9232]

at the end, is that required practical 10?

[@Maya-wt9dh]

10a

[@mechackkaba8578]

Wonderful

[@hadiadaoud1317]

Hi sir, for acyl chlorides reacting with a primary amine, wouldn't it be CH3NH3+CL- instead of HCL

[@nedbowlas913]

Chemguide states very little HCl as any formed would react with the amine and form and salt.

[@henryindia8195]

so is biodiesel the methyl ester or a faty acid? 29:50

[@vanessayeung...]

it is a mixture of different fatty acid methyl esters, so aka mixture of methyl ester of longpchain carboxylic acids.

[@lol.1296]

Bio diesel is the methyl ester

[@h.n2826]

The methyl ester

[@gorirad1738]

Thank you so so so much

[@AS-mw6pw]

Do we need to know the mechanisms for the Acid Anhydride reactions, or only the Acyl Chloride reactions? (AQA)

[@lc6923]

only acyl chloride

[@behappy1452]

no, the spec says acyl chloride use it it helps to check :)

[@creepylina]

the specification says: "Students should be able to outline the mechanisms of: these nucleophilic substitution reactions the nucleophilic addition-elimination reactions of ammonia and primary amines with acyl chlorides."

[@nerdymathematician]

thank you🥰🥰🥰

[@AlleryChemistry]

You’re welcome 😊