B.P1 B.P2 B.M2 B. D2 Criteria's Met.
Learning Aim B: (Distinction - Analyse the effects of Monosubstituents on the benzene ring to predict further substitution position(s) of a reaction species on the benzene ring. This assignment will Gaurantee you a Distinction Achieved Distinction first time....
Pearson BTEC Level 3 National Extended Certificate in Applied Science
Unit 14: applications of organic chemistry
Assignment B
Learning aim B: to understand the reactions and properties of aromatic compounds
Ms qureshi
Hybridization, sigma, pi bonding, and delocalisation of electrons of the structure of
benzene
During hybridization an electron from 2s orbitals is transferred to an empty 2p2
orbital The 2s orbital, 2px orbital, and the 2py orbital hydride to form sp2 hybrids
leaving the fourth p orbital unchanged. In the carbon it demonstrates how 3 of its
electrons gets pulled in different directions except for its 4th electron in the 4th
orbital which remains unchanged. the 3 electrons in the carbon atom 2s orbital,
2px orbital, and 2py orbital are separated from each other at a 120 degree angle
, During a sigma bond it
demonstrates how the
2 electrons from each
carbon atom attracts
therefore overlaps
with each other
forming a single bond (sigma bond) where as the 3 rd electron from each carbon attracts
its electron with each hydrogen electron therefore the electrons overlap forming a C-H
bond
During the pi bonding it demonstrates how
each fourth unchanged P orbital attracts its delocalised electron with another therefore
causing the delocalised electrons to overlap forming pi bond and 2 delocalised rings
X ray evidence
,Using X ray diffraction single C-C bonds in kekule structure was measured to be 0.154nm
however using x ray diffraction to measure double C-C bonds it suggest how it gave a
measure of 0.133nm which therefore disproved the original kekule structure as it suggest
how single C-C bonds and double C-C bonds had different lengths therefore making the
kekule structure fairly unstable and irregularly shaped however when using x ray
diffraction to measure the bond lengths of the modern benzene structure is
demonstrates how they were all measured to be 0.139nm which therefore implies how
the modern kekule is very stable and regularly shaped as they only contain single C-C
bonds
Thermochemical
analysis evidence
Using
thermochemical
analysis it demonstrates when using cyclohexene react with H2 it implies how it has an
enthalpy change of 120 KJ mol of heat as it shows how the double C=C bond and H-H
bond in cyclohexa-1,3-5 diene broken and the 2 CH groups become CH2 with a single
bond attach to them however when reacting benzene with 3H2 as it demonstrates how
kekule predicts it would have an enthalpy change of 360 JK mol as it suggests how 3
double C=C Bonds and 3 single H-H bonds are broken however it shows how how the
real benzene has an enthalpy change of 208 KJ mol which therefore suggest how how
the real benzene does contain 3 double C=C bonds and is roughly 150 KJ more stable
than the kekule structure
,Infrared evidence
In the infrared spectrum it demonstrates how C-H stretches in benzene occur roughly at
3000cm in the spectrum. It also shows how C-H bending stretches occur at 1500 cm in
the benzene ring. Furthermore it implies how C-C stretches occur at 1500-1800 cm in the
benzene ring.
Reactions of benzene
It shows how benzene reacts with concentrated H2SO4 to form benzenesulfonic acid
Conditions
,Heat under reflux with Concentrated sulfuric acid (H2S04)
Equation
Where one hydrogen from benzene is removed and bonds with one oxygen from the SO3
electrophile in which the SO3 group is substituted into the benzene ring to form benzene
sulphonic acid
It suggest how the benzene is important and suitable in industrial reactions as it
demonstrates how it can be used in further substitution reactions to make dyes, color
intensifiers, and pharmaceutical products
Benzene reacts with nitric acid to form nitrobenzene
Conditions
Heat under reflux with concentrated sulfuric acid at 35 degrees
Equation
C6H6 + HNO3 = C6H5NO2 + H20
Where it demonstrates how
one hydrogen from
benzene is removed and is
replaced with NO2
electrophile from nitric acid
to form nitrobenzene. the
hydrogen removed from
benzene and the hydrogen
and 1 oxygen removed from
nitric acid forms a water
molecule H20
Reactions of phenol
It demonstrates how phenol
reacts with alkalis to
produce a salt and water
E.g phenol reacts with
NAOH to produce sodium
phenoxide and water
, Conditions
Concentrated H2SO4
Equation
Where it shows how the hydrogen form
the OH group in phenol is removed and
substituted with NA from NAOH
producing sodium phenoxide it also
implies how the hydrogen removed
from OH group in benzene and the OH
from NAOH bonds also form a water molecule H20
Phenol reacts with bromine to form 2,4,6-tribromophenol
Conditions
Concentrated nitric acid
Equation
Where it shows how 3 hydrogens in the 2,4,6 position in the benzene ring in phenol is
removed and replaced by 3 bromine atoms to form 2,4,6-Tribromophenol
Phenol is important in the industry as it used to make explosives, plastics, and
pharmaceutical drugs
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