Carboxylic Acid Flashcards
Why cooh high BP
1.Carbonyl group of cooh withdraws electron more polar OH bond, giving rise to stronger hydro bond
2. Cyclic dimers held by hydro bonds, doubling size, ^idid
Why solubility of carboxylic acid decrease as molecule size increase?
Same as alcohol and carbonyl, as larger R makes it more hydrophobic, energy released comes from idid rather than hydro bond(h2o to either =o or OH, both can), which is no enough to overcome hydro between h20 and cooh respectively
Why cooh stronger acid than alcohol or phenol
-ve charge dispersed over c atom and both electronegative O so more dispersed and stable than phenoxide or alkoxide
What are the 2 cooh that can further oxidise
Methanoic acid with kmno4/K2cr2o7(dil h2s04) /tollens and fehlings +heat can oxidise to get co2 and h2o
Ethanedioic acid with kmno4 dil H2so4 heat also co2 and h20
How to test for cooh
Gas evolved form White ppt with ca(oh)2 with na2co3
Anhydrous pcl5 white fumes of hcl evolved.(alcohol also and anhydrous cause pcl5 hydrolyse to get white fumes also)
Why acyl chloride and ester lower BP and more volatile than rcooh
Weak pdpd
Why ester less soluble than acyl chloride
Hydrolysis slower for ester cause of 2 hydrophobic R groups
Why is acyl chloride a stronger acid in water than rcooh
Hcl produced from hydrolysis
Why order of reactivity for nucleosub goes acyl chloride>alkyl chloride> aryl chloride(chloro benzene)
No of electronegative stuff, makes the c less electron deficient, but for aryl the lp delocalise into benzene, c-cl strong partial double bond, no nucleo sub normally
Why basic hydro of ester into alcohol and cooh not reversible like acidic hydrolysis?
Oh- stronger nucleophile than h20(in acidic hydro), 1 way into o-na+ carboxylic salt.can acidify the salt to form rcooh
