this is some basic principles and question & answers of previous years of organic chemistry with notes on dr.emad manhal's examination , school of pharmacy , university of sulaimani .

1. Organic Chemistry
Principles & Questions and Answers
UOS/Faculty of medical
sciences
School of pharmacy Second stage

2. Basic Principles
- What is carbocation ?
Carbocation is a carbon with positive charge or carbon
with sixtet electron it means it has only six electrons in its
outer valence shell instead of the eight valence electrons
that ensures maximum stability (octet rule) .
- When polarity occurs ?
Polarity occurs between different atoms or different
sizes and different electronegativity .
Note/ Br2 is heavy gas , it is not polar .
- What is electrophile ?
Ion positive or group of atom poor in electron.
- What is nucleophile ?
Ion negative or group of atom rich in electron.

3. Note / in organic chemistry always negative
charge ( nucleophile ) attacks the positive
charge ( electrophile ) .
-How electron movement occurs in organic
reactions ?
Electron movement can be shown in curved-arrows .
Note / in the beak down or clavage of bond
between molecules the direction of arows
must be from + charge ( tail ) to – charge
(head ) as follow :

4. Or from the double bond to adjacent bond
or from double bond to adjacent atom or
from atom to adjacent bond as follow :
Note / you must always draw the arrows in
right direction in the mechanism.
- What is solid and dashed wedges ?

5. - What are the types of hydrocarbon ?
There are two types of hydrocarbons :
Saturated hydrocarbon and unsaturated hydrocarbon .
- What is saturated hydrocarbon or
saturated compound ?
Is a compound contain only carbon-carbon single bond .
- What is unsaturated compound ?
Is a compound contain carbon-carbon double bond .
Note / Halogens in unsaturated compound is
polar .
- What is degree of unsaturation ?
number of cycles or double bond in organic compound
( pi bond ) not only carbon-carbon double bond .
Note / Triple bond-allkyne also unsaturated
hydrocarbon .
- Stability of ion depends on what ?
Stability of ion depends on density of charge :

6. As density of charge small the stability of ion large . How
? to make density of charge small or decrease you can
add group releasing electron ( alkyl group ), alkyl group is
group releasing electron so stabilize positive ion and
dcrease density of charge .
Note / As the intermediate more stable ,
more possible to form ( that’s why we
always do rearrangement ) .
- Explain Stability of carbocation ?
As number of alkyl group bonded to carbocation increase
the stability of carbocation increase .
- What is rearrangement of carbocation ?
Carbocation is able to produce carbocation that is more
stable by shift { 1 , 2 } of hydrogen or alkyl group .
Note / As number of alpha hydrogen
increase the stability increase . that’s why

7. some times minor and major product is
formed .
- What is alpha hydrogen ?
Alpha hydrogen is a hydrogen attached to the carbon ,
that the carbon attached to the carbon-carbon double
bond .
Note / Elimination reaction only occurs in
medium basic .
Note/ Always we can remove acid by base
-What is markovinkov's rule ?
In markovinkov's rule , Hydrogen will go to the side that
high of hydrogen and halide will go to the side of low
hydrogen .
- when markovinkov's rule occur ?
In addition reaction ( ionic reactions ).

8. - when anti-markovinkov's rule occurs ?
In free radical or substitution reaction.
Note / for anti-markovinkov's rule to occurs
it needs HOOH or UV light .
Note / HOOH or H2O2 (Peroxide) is a donor
of oxygen .
- what happens in transition state ?
In transition state bond making and bond breaking occur
. it is unstable due to carbon pent . energy of state is high
.
Note / always you need to mention this
explaination in examination .

9. - how can we prevent rearrangement ?
We can prevent rearrangement by heating .
CH3-CH2-CH3 + HCl ---------
CH3CH2ClCH3
- how many typesof intermediateavailable ?
Three types :
-Carbocation .
-Free radical .
-tansition state .
- What is free radical ?
uncharged molecule (typically highly reactive and short-
lived) having an unpaired valence electron ( means
having one electron )
- What is theory of resonance ?

10. Resonance is the delocalization electron or charges or
free radical of system conjugated and planar .
- why alkane is more stable than alkene and
alkene is more stable than alkyne ?
Because as the number of Pi bond increase the stability
decrease , it means that alkane has the lowest energy .
Note / Halides in medium basic are good
leaving group .
-what is tautomerism ?
Production of enol form in equilibrium with keto form .
- Why conjugated diene is more stable than
alkene ?

11. Due to resonance which produce enthalpy less and
entropy of the system is high .
Note / According to mass :
Br > Cl > O > N > C
- What is NBS ?
N-Bromosuccinimide or NBS is a chemical reagent used
in radical substitution and electrophilic addition reactions
in organic chemistry. NBS can be a convenient source of
Br•
Note / you need to know the structure of
NBS , it is not given in exam .
-what is the common name of ethyne ?
Acetylene .
Note / but acetylide is an anion formed by
removing the proton from the end carbon of
a terminal alkyne.

12. - Why products are always trans ?
Because trans is more stable than cis .
- What are the differences between SN1 and
SN2 ?
The reactions of SN1 is slow , the intermediate is
carbocation , shift (rearrangement ) can occurs .
The reaction of SN2 is fast , the intermediate is transition
state , the shift cannot occur .
- How to choose SN1 or SN2 ?
If the halogen was 1⁰ we need to use SN2 reaction
If the halogen was 3⁰ we need to use SN1 reaction
If the halogen was 2⁰ we can use either SN1 or SN2
depends on the product either O.Inactive or O.Active.
Note/ The product of the SN2 reactions is
always optically active , the product of SN1
reactions is always optically inactive .
Note/ E2 is the same of SN2 .
E1 is the same of SN1 .

13. Examinations of organic
chemistry
-Types of questions are usually mechanisms , Synthesis ,
Explanaition , Classification of Carbon , Drawing the
structure , Uv Spectroscopy ( in first course ) .How ? This
is two examples of question paper :

14. Organic Chemistry
Second Year Pharmacy

15. Q1.Give the mechanism of the following reactions :
1)Cyclo hexane + Br2/hv -------> Bromo cyclo hexane
2)Hydroxy butane + H2SO4 conc. --- Alkene
3)3-methyl butene + Hbr ----- Bromo alkane
Q2. Explain the following concepts :
1)Allyl carbocation more stable than tertiary carbocation.
2) Tautomerism .
3) in butane molecule anti-conformation is more stable
than gauche conformation .
The answer is 239nm
Notes on Mechanisms:-1

16. First you need to know all the mechanisms in the handbook
( Step by step )
Then the reactant always changes ( reactant are not the
same as handbook ) so try to understand the steps of
mechanism .
Rearrangement , Bridge ,Always rembemer to mention :
Good leaving group , Transition state .
Notes on Explainations:-2
This type of question is limited and they are not change.
Notes on Synthesis:-3
Synthesis is not something that posses in the handbook and
it is not the preparation , it doesn’t requires mechanism ,
synthesis is just one step, how ? .it is very easy and it requires
you only to choose a good solvent ( reagent ) that’s why
synthesis all depends on how did you undersand the
mechanisms . it means How do u prepare the product that
given by using the special solvent . for example :
Try to synthesis the following :

17. -Synthesis Hexyne from Ethyne :
it means if u have ethyne how can u prepare hexyne from it ?
any halogen inremember the note that we saidyouifTIP/
↑.medium basic is good leaving group
- Synthesis propanol from propene or synthesis propanol
from alkene :
- Synthesis 2-propanol from propane :
-Synthesis 2-Bromo Propane from Propene :

18. -Synthesis bromo propane from propene :
-synthesis Acetone ( ketone ) from propyne :
.classification of carbonotes onN-4
In this type of question , it is needed to name all the carbons
in the given structure .
- all You need to know :
Primary carbon , Secondary carbon , Tertiary carbon ,
quaternary carbon , Vinyl Carbon , Methyl carbon , Alpha
carbon , allyl carbon .
1- primary carbon is a carbon bonded with one carbon.
2- Secondary carbon is a carbon bonded with two carbon.
3- Tertiary carbon is a carbon bonded with three carbon .
4- Quaternary carbon is a carbon bonded with 4 carbon .

19. 5-Vinyl carbon : is a carbon posses double bond with another
carbon .
6- Allyl carbon : is a carbon atom bonded to a carbon atom
that in turn is doubly bonded to another carbon atom.
7- Methyl carbon : is a carbon that not bonded to another
carbon .
(exams) :sin given structureof carbonesClassIdentify the
2-methyl 2-pentene

20. -2017 examination : identify the classes of carbon from
1,2-diethyl cyclohexene
Solution :

21. :she following compoundin tcarbonslassify tTry to c
Draw the structure :Notes on-5
This type of question can be asked in stereochemistry
chapter . for example :
Draw the structure of the following :
2S-Hydroxy , 3R – Methyl hexane
Solution :

22. 2R-Phenyl ,3S-Chloro , 3R-phenylpentane
:UV spectroscopy-6
Every years one of the questions is UV spectroscopy
the numbers and rules are given in the question paper . BUT
you need to know that EXOCYCLIC is always ONE and that is
CONSTANT ( DON'T COMPARE THE EXAMPLES OF THE BOOK
TO THE INTERNET EXAMPLES BECAUSE DR.EMAD HAS ITS

23. OWN WAY AND ITS DIFFERENT FROM THE REFERENCES OR
INTERNET EXAMPLES )
For example : in the examples below I have solved the
questions in dr.emad's way also you need to solve in this way
.
If there is another lectuerer , Solutions may be changed .
Find the lamda max for the following compound :
Questions and Answers
( previous years examination are also included )
-Explain the following concepts :

24. 1) what are the conditions of resonance ?
Resonance occurs in any conjugated system and planar .
2) Diene is more reactive than alkene ?
Diene is more reactive than alkene due to intermediate of diene
is more stable than intermediate of alkene due to resonance .
Energy of the diene is less than the energy of the alkene which is
high .
3)Trans form is more stable than cis ?
Because in trans form distance between big groups is large also
van der waals repulsion force is low and energy of the system is
low therefore more stable , whereas in the cis form the distance
between big groups is small and van der waals repulsion force is
high and the energy of system is high .
4) Racemic modification is optically inactive ?
Racemic modification is optically inactive due to it contains two
equal amount of enantiomer , each one of them rotate the

25. plane polarized site to the other , so they cancel each other and
the value of alpha is zero . one rotate in R and another in S , so
they cancel each other .
5) Differences between enantiomers and diasteromers ?
Enantiomers : 1- they mirror image each other , 2- they have the
same physical properties , 3- at least they contain one or more
chiral center .
Diasteriomers : 1- not mirror image of each other , 2- they have
different physical properties such as density , m.p ….
3- They contain two or more chiral center .
6)Basic theory of Uv spectroscopy ?

26. UV spectroscopy is dealing with system conjugated ,also uv
technique is physical and optical technique , which is the
electron transition between HOMO and LUMO that allows to
detect conjugated system inside organic compounds .
7) Tautomerism ?
Tautomerism is the equilibrium between the alpha hydrogen of
keto-form and enol-form .
8) Allyl carbocation is more stable than tertiary carbocation ?
Allyl carbocation is more stable than tertiary carbocation due to
resonance which makes it to has low enthalpy and high entropy
.
9) differences between racemic modificartion and
mesocompound and their relationship ?
In mesocompound the same molecule is mirror image between
two half of the molecule but in the racemic modification it is not
inside one molecule . also they are both optically inactive with
alpha of zero .

27. (Meso comound) (Racemic modification)
10) Halogens are ortho-para direction while deactivating
group ?
Due to mesomerism effect they direct ortho-para direction
rather than meta direction . as follow :
11) Nitrobenze is more stable at meta than ortho-para ?

28. Try to synthesis the following :
1- 2-chloro propane from isopropyl alcohol .
2- 2-hydroxy butane from 2-bromo butane .
3- Bnezophenone from benzene .
4- Phenyl ethanone from benzene .
5- Bnezyl benzene from benzene .
6- m-isopropyl nitrobenzene from benzene .
7- P-methyl , M-bromo acetaphenone from benzene .
8- 1,2-dimethyl , 3,3-dicloro cyclopropane from propene .
9- Cyclohexenoxide from cyclohexene .
10- butyne from 1,2-dihydroxy butane.
11- Acetone from propyne .
Solutions :

29. 1-
2-
3-
4-

30. 5-
6-

31. 7-
8-
9-

32. 10-
11-
Good Luck😊
Thursday , august 3 , 2017 Bryar R.R Ali Russ