Organic chem Flashcards
Isomers with 4 C
2
Isomers with 5C
3
isomers with 6 C
5
Isomers with 7C
9
Isomers with 8 C
18
Isomers with 9C
35
Isomers with 10 C
75
Resonance effect
Effect due to resonance, if charged centers are developed
e’ donating grps
CH3, NH2, NR2, NHR, OH, OR, X
e’ withdrawing grps
CHO, CO, COOH, CN, COX, CONH2, COOR, NO, NO2
Inductive effect
Polarisation produced in a σbond due to diff in e’ -veity b/n atoms
I effect inversely prop to
dist b/n atms
-I effect order
NR3>NO2>CN>SO3H>CHO>COOH>F>Cl>Br>I>OH>NH2
Hyperconjugation
Migration of Ch σ bond e of sp3 to sp2
Hyperconjugation also known as
Baker Nathen effect
H.C prop to
No of α H
stability of C+
3>2>1*
Electromeric effect
If attacking reagent comes to same C, to which the π e’s migrate, it is +E effect, otherwise -E effect
Huckel’s rule
Cmpd must be cyclic, planar, conjugated, have 4n+2 π e’s
Effects order
Aromatic>+R>+HC>+I
Carbenes
Neutral e’ deficient reactive
Polar protic solvents
Solvent which can give H+ like ROH, H2O, RCOOH
Sublimable solids
Camphor, iodine, benzoic acid, phthalic acid, indigo, anthracene, hexachloroethane
Non sublimable solids
sand and salt
Benzoic acid & napthalene can be separated by
crystallisation
salicylic acid & aspirin can be separated by
Crystallization
Anthracene & urea can be separated by
crystallization
If very little OC is in large vol of solu we use
differential extraction
Benzene & nitrobenzene can be separated by
simple distillation
acetone & propanol can be separated by
simple distillatio
For simple distillation
cmpd should be volatile, no decomposition at high T, large diff in BP
If diff in BP is low we use
fractional distillation
For fractional distillation
cmpd must be volatile, no decom at high T, BP diff must be less
Crude oil can be separated by
Fractional distil
amines can be separated by
Fractional distil
ethanol & acetone can be separated by
fractional distil
If cmpd decomposes at high T, we use
Steam distil
For steam distil,
cmpd must be steam volatile, immiscible with water
salicylaldehyde & p hydroxybenzaldehyde can be separated by
steam distil
essential oils can be separated by
steam distil
If cmpd is not steam volatile & immiscible with water we use
distillation under reduced press or vacuum distil
Glycerol in spentlye can be separated by
vacuum disil
sugar can be separated by
vacuum disil
Column chromatography is
acc to gravity
Thin layer chromatography is
against gravity like capillary rise
Adsorbent
site at which adsorption takes place
adsorbent eg
SiO2, Al2O3, TiO2, starch, charcoal
Adsorbate
particles undergoing adsorption
Stationary phase
adsorbents
Mobile phase
solvent like benzene, toluene, CHCl3, CCl4
Retention factor r(f) =
Dist travelled by each component/dist travelled by solvent front from baseline
Partition chromatography
water act as stationary phase
Amino acids can be separated by
partition chrom
proteins can be separated by
partition chrom
Visualizing agents
UV lamp, I2 vapours in I2 chamber
test for C & H
OG + CuO gives CO2 + H2O turns lime water milky and forms blue ppt of CuSO4.5H2O
Lassaigne’s test for
N,S,X
Lassaigne’s test
OC + Na gives NaCN/Na2S/NaX/NaSCN
For N
Prussian blue ppt of Fe4[FeCN6] from NaCN
Which doesn’t give blue ppt
Diazonium salt, diazomethane, hydrazine, NH2OH
For S
Na2S + CH3COOH with sodium nitroprusside gives purple sod. thionitroprusside
with Pb(CH3COO)2 gives black PbS
with Cd(CH3COO)2 gives yellow CdS
For X
AgCl gives white with AgNO3 - soluble
AgBr gives pale yellow - partially soluble
AgI - yellow - insoluble
For elimination of CN & S
NaCN/Na2S + HNO3 boil
NaSCN with CH3COOH + FeCl3
Blood red ppt [FeSCN]2+
For C & H
Liebig
For N
Duma’s & Kjeldahl’s method
CxHyNz + CuO heat gives
xCO2 + y/2H2O + z/2N2
Vstp =
[P(T) - P(H2O)]V1 x 273/760xT1
%N =
28/22400 x Vstp(mL) x 100/W
Limitation of Kjeldahl’s method
Can’t estimate nitrobenzene, azo & diazo cmpds
For X
Carius method
%X
At. wt of X x W(AgX) x 100/MM of AgX x W(oc)
For S
Carius method
%S
32xW(BaSO4)x100/233W(oc)
%P
31W(o)x100/1877W(oc)
BP prop
No of C
Reactivity of H prop
stability of free radical(3>2>1*)
Reactivity of X
F2>Cl2>Br2>I2
Which will only react with KMnO4 to give alcohol
3* alc
n-hexane to benzene
Cr2O3 773K, 10-20atm
Stability of conformations
Staggered>skew>eclipsed
CaC2 + H2O
CHCH
alkynes stability
3>2>1*
CHCH to C6H6
red hot Fe 873K
C6H6 to Gammahexane
3Cl2 hν/500K
Gammahexane also called
Lindane