GENARAL CHEMISTRY
First year students
Al-Hadba University
Medical Laboratories
Techniques Department
Prof.Dr.Ahmad kh. Alkhayat
2024 - 2025
+Experiment - 3
Reaction of some organic compds. (Aliphatic, aromatic, alcohol, aldehyde &
ketone)
Reaction of aliphatic compound
• Oxidation & heat of combustion
Burning (combustion) of hydrocarbon takes place only at high
temperature (flame or spark) to produce CO2 , H2O & heat
CH4 + O2
flame
CO2 + H2O + heat (213Kcal. /mol )
• High-temp partial oxidation of methane gives
CH4 + O2
1500C0
_
2 H-C=C-H
+ 2CO2 + 10 H2
Catalytic oxidation of methane in the presence of H2O gives H2 & •
CO
CH4 + H2O
0
850C / Ni
H2 + CO
3- Pyrolysis: Cracking
Decomposition of a compound by the action of heat alone is known as
pyrolysis. (Cleavage by heat), compare hydrolysis, cleavage by water.
Reacti
on of
alken
e
1- Alkenes are readily converted by CL2 or Br2 into saturated
compounds.
CH2= CH2 + Br2 /CCL4
r.t.
orange
Br
Br
colorless
2- Reaction of alkynes ( acetylene)
H3C
CH2
C
CH
1-Butyne
A terminal alkyne
AgNO3
H3C
CH2
C
C
Ag
Precipitate
H3C
C
C
CH3
Ag+
no reaction
Reaction of aromatic compound
1- Ignition test
Aromatic compounds, which does not contain oxygen burns with dark
smoke
2- The chloroform-Aluminum chloride test
3 C6H6 + CHCL3
AlCL3
( C6H5)3CH + 3 HCL
yellow-orange or red
blue or purple
green or pink
Reaction of alcohol
• Xanthate test…. General test for alcohol
ROH + KOH
heat
ROK + H2O
ROK + CS2
ROCSSK
potassium alkyl xanthates
yellow ppt.
• Lucas reagent ( ZnCl2 / HCL)
RCH2OH + ZnCL2/ HCL
1
RCH2CL + H2O react with long time
0
R2CHOH + ZnCL2 / HCL
2
react with in 2-3 min.
R2CHCL + H2O
0
R3COH + ZnCL2
R3C-CL + H2O
react immediatly
Reaction of aldehyde & ketone
• 2,4-dinitrophenylhydrizine
General test for aldehyde & ketone
R
HN
O
N
NH2
HN
NO 2
C
R
R1
R1
+
NO 2
NO 2
+
H
+ H2O
NO 2
Yellow or orange ppt.
• Tollens reagent
Contain the silver ammonia ion, Ag (NH3)2+. Oxidation of the
aldehyde is accompanied by reduction of ion to free silver (in the form
of a mirror under the proper condition)
AgNO3 + NaOH
AgOH + NaNO3
AgOH + NH4OH
Ag(NH3)+2OH + H2O
RCHO + Ag(NH3)+2OH
Colorless
solution
5
RCOO- + Ag
Silver
mirror