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Chemistry A Level CIE Electrochemistry
Chemistry A Level CIE Electrochemistry
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ethanol (H50H = C2H50+
-
: + H
(2H5 >
-
donating
more If react more with Ht eam to left
Carboxylic Acid and their
Derivatives , ,
·
Acidity
CH3COOH (99) = CH3C00- (d9) + H+ (aq) Phenol :
CoH5OH = CoH5O- + Ht
·
equ Electrons go into ring ,
Carboxylic Acid> Phenol > Water > alcohol Overlap Disystem >
-
More stable
I
less Acidic charge then spread over ,
↓ pla ,
more acidic Reduced ,
not (f
enough to
-
O-H bond weakened by Carbonyl group c = 0 reactWith Ht +O fOrM CbH5OH
>e
-
withdrawing
O
ce-in C-0 bond drawn towards c= 0 bond Ti
C-OH
-
R -
C > e-drawn away NO2 >
-
With draw
-
m
e-withdrawing O - H ↓
Withdraw
↳ more Electronegative
-
Carboxylate ion is stabilised by delocalisation of earound Cof-group . This delo calisation spreads out the
negative charge on Carboxylate ion , reducing its charge density and making it less likely to bond
With an H +
(ag) ion to re-form the undissociated acid molecule
O
negative charge is spread over the whole-coo-group (bonblengths of both
" >
- Carbon-oxygen
B -C
-
bonds are equal)
"
-
chlorine is e-withdrawing group
↳ e-withdrawing groups extend the delocalisation of the negative on the -coo-group of the carboxylate
ion , further increasing the stabilising of the-coo-group and making it less likely to bond with an Ht(aq) ion
"
O O
H-C--O-H H--r H +
Tka , stronger acid , tipka
H H more stable
the more the Ci
stronger acid
,
more de localised
,
ka = 1 3 x 10
-
3 due to CI group
10 5
.
I Ka 1 7
-
Ethanol : = . x
e Cl
* methyl group - donating O
* /
LI E C
↳I
-
↳ strengthens the O-H bond in -C00H
- -
It
donates (f charge towards 100-
Cl
*
easily and
-
↳ If lost most
the CC13c00-ion
group of carboxylate ion > more
-
likely formed is least Attractive
to H+ (aq) ions , nence
accept H (aq) ion H (99) ions dissociated
+
to More +
,↑ now benzoic acids are formed
Alkylarenes
>
-
Alkane side chain oxidised to -cooH only
1 . Why Ethanoic acid is a stronger acid than ethanol .
e-withdrawing Carbonyl ethanoic Acid weakens the O-H bond in-COOH
>
-
group in group
,
making it more likely for CH3200H to lose an Htion than CzH50H. Delocalisation of e-
around-coo-group stabilises the ethanoate ion
. Not possible in ethoxide ion >
-
only has electron
donating group Calkyl) ,
less likely to It
lose since less delocalised e
2 . Methanoic Acid us ethanoic acid
>
-
Ethanoic did has more electron donating group , hence doesn't did the breaking of O-H
Methanoic acid >
stronger acid. Once the ethanoate anion is formed the methyl group
-
tends to increase the concentration of 1 charge on the -200-end of ion >
-
more attractive
to #tions than Methanoate .
anion Hence ethanoic did more likely exist undissociated.
·
oxidation
-
Methanoic did is a stronger reducing agent than other carboxylic acids
↳ Feeling's solution
-
Alkaline Sol . Contains Cu2 + ions (blue)
red/orange
+
-
clear blue-opaque (c) )
↳ Tollen's reagent
-
ad - solution of AGNOs in excess NH3 SO1 .
-
silver ions reduced to silver atoms
+
HCOOH CO2 2H (ag) warmed with Felling's
> + + 22-- under /Tollen's
-
I H2OOH + [O] >
-
CO2 + H2O Acidified KMnOD/K2CUzO7
, -
stronger of can oxidise ethanediois acid
④
OH-c-C-OH
Ethanedioic acid + H2SO4 can be used to stardadise kMnO4
O O
"
1
CH2 -
(H2 -
-
0 -
H < CH3 -
CH -
C -
O -
H
it it
more with drawing
Since closer to 0-
More Acidic
Acyl Chloride
O
I
R -
C -
C
·
synthesis
+ PC13 neat
warm
carb acid .
+ SOCIz > Acyl Chloride
L
rEP
+ PC15
eX : 3CH3C00H + P(1zMeg 3CH3202I +
HyPOz
r . t .
(9)
CH3COOH + SOCI + CH3COCI + SO2 + HCl(g) ,
no need further distillation
CH3C00H + P(15 CH3COCI + POCI + HCl
↳
steamy fumes
·
Reactions
1 .
Hydrolysis
Acy1 > halogenoalkane > chlorobenzene
↓
paling gampang react
-
c
iii St
R
> R -
CH2 -
Cl > one pair of 11 overlap it ring system
C Cl
-
- .
>
-
>
-
↓ most (+ >
L
delocalised over conjugated double
boud ring of benzene adding ,
highly st carbon atom bonded to its character .
to electronegative o and ch Due to double bond character
chlorine of ary) ring
is Mert bond
, strong c-cl .
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