Sch2108:Organic Chemistry Question Paper
Sch2108:Organic Chemistry
Course:Bachelor Of Horticulture
Institution: Meru University Of Science And Technology question papers
Exam Year:2013
QUESTION ONE (30 MARKS)
a) Give IUPAC names of the following compounds; (6 Marks) i) CH2 CHCH CH2 CH3
ii)
iii) H C C C H
O HH
H H
b) Show and name all the structures of the compound with molecular formulae. (4 Marks) i. C4H10
2
ii. C2H6O c) Give the names of the functional groups represented by the following structures. (4 Marks)
i) C C OH
O
ii) C C C
O
d) i) Using electronic orbital diagrams, show how sp3 hybrid orbitals are formed in the carbon atom (c=6). (4 Marks) ii) Describe the bonding in the formaldehyde molecule, H2CO in terms of atomic orbital overlap identifying the ?? and ?? bonds. (4 Marks) e) Complete the following chemical reactions showing all the intermediates where necessary. (8 Marks)
i) CH3C CH + H2O
H2SO4
HgSO4
ii) CH3CH3+Cl2 iii) CH3CH2OH+CH3COOH
iv) CH3C HCH3 Na2Cr2O H2SO4 OH
QUESTION TWO (20 MARKS)
a) Assign the E and Z stereochemistry to the following compounds. (6 Marks)
i) C C
H
CH3
C
CH3
CH2
H
3
ii) C C
C
CH
CH3
H3C
H2C
H
Br
H
iii) C C
CH3
H CH2OH
C
O
OH
b) Show how you would prepare the following carboxylic acids through a Grignard synthesis. (6 Marks) i. 2,2 – Dimethylpropanoic acid ii. Hexanoic acid
c) Give an equation to show how you can prepare acetic anhydride, CH3 C O C CH3
O
O
(4 Marks)
d) Benzoic acid C6H5 COH
O
reacts with methanol, CH3OH to form an ester
C6H5 C OCH3
O
, using an acid catalyst (H+), show the reaction mechanism for this reaction. (4 Marks)
QUESTION THREE (20 MARKS)
a) Give two acceptable names for each of the following compounds. (6 Marks)
i)
Br
Br
4
ii)
Cl
Cl
SO3H
HNO3
H2SO4
b) Benzene reacts with bromine in presence of a Lewis acid as shown
+ Br2
FeBr3
heat
Br
+ HBr
If FeBr3 is generated insitu during the reaction, i. Write an equation to show how FeBr3 is produced. (2 Marks) ii. Write a reaction mechanism to show how the bromide ion, Br- is produced. (2 Marks) iii. Show the reaction mechanism for the formation of; Br
(4 Marks) iv. Identify the arenium ion formed as an intermediate in the process of formation of the final product. (2 Marks) c) Show the major products of the following reactions; i. Nitration of methylbenzene (2 Marks) CH3
HNO3
H2SO4
ii. Nitration of benzene sulphonic acid (2 Marks)
5
SO3H
HNO3
H2SO4
QUESTION FOUR (20 MARKS)
a) Using relevant examples explain the following; i. sp2 hybridization (2 Marks) ii. sp hybridization (2 Marks) b) Sketch to illustrate the electron density of sp3 hybrid orbitals. (2 Marks) c) C4H10 is an unsaturated hydrocarbon; i. Draw a line-bond structure for the given compound and indicate the type of hybridization on each carbon atom. (3 Marks) ii. What kind of covalent bonds are observed in alkenes? (2 Marks) iii. Show and name all the isomers of the compound, C4H10. (3 Marks) d) Write equations to show how you can prepare CH3CH2COOH from i. An alcohol ii. An alkylhalide via a Grignard reagent. (2 Marks) iii. An acylchloride (2 Marks)
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