TEST 1, answers chem 102 organic chemistry PDF

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CHEMISTRY DEPARTMENT UNIVERSITY OF BOTSWANA CHE 102 GENERAL CHEMISTRY II 5th March 2019

TIME ALLOWED: 2 HOURS

Surname:.………………………………………. Other names:………………… Student ID No.:…………………………..

1. Answer ALL the questions 2. You are allowed to use molecular models

3. WRITE ALL ANSWERS IN INK The paper has 10 printed pages

DO NOT WRITE IN THIS TABLE MC

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SECTION A Answer ALL questions in this section by circling the correct answer in each question. (60 marks, 3 marks each) 1. The hydrocarbons with general molecular formula CnH2n, belong to the class of A. B. C. D. E.

alkyne and cycloalkane cycloalkene and cycloalkane cycloalkene and alkyne alkene and cycloalkane alkene and cycloalkyne

2. What is the correct molecular formula of the compounds with the following line formula?

A. B. C. D. E.

I: C5H12O; II: C5H10; III: C6H6Br I: C5H12O; II: C6H12; III: C6H5Br I: C5H10O; II: C6H12; III: C6H6Br I: C6H12O; II: C5H10; III: C6H5Br I: C5H12O; II: C5H12; III: C6H6Br

3. What are the hybridizations of the carbons X, Y and Z?

A. B. C. D. E.

X =sp3, Y =sp, Z =sp X= sp2,Y = sp, Z =sp3 X =sp2,Y = sp,Z = sp X =sp3, Y =sp2,Z = sp X = sp, Y= sp, Z= sp2

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4. How many sigma bonds are present in the following molecule?

A. 15

B. 12

D. 9

C. 11

E.

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5. Arrange the following compounds in order of decreasing boiling point. i.e. from the highest to the lowest.

A. 1>2>3>4 B. 4 > 3 > 2 > 1 C. 4 > 2 > 3 > 1 D. 1 > 3 > 2 > 4 E. 3 > 2 > 4 > 1 6. For the following structure there are…….1,…..2 ,…..3 and …..4 carbon atoms.

A. B. C. D. E.

3, 1, 3, 2 4, 3, 1, 1 4, 2, 2, 1 2, 3, 1, 2 3,2,1,2,1

7. Which of the following compounds will show cis-trans isomerism?

A. B. C. D. E.

I and IV I and III I and II II and IV II and III

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8. The reaction of isooctane with excess oxygen is known to release heat energy. The chemical products of the reaction are--------------. A. carbon and hydrogen B. water and carbon dioxide C. hydrogen and carbon dioxide D. water and carbon E. carbon dioxide and carbon monoxide 9. Which one of the following compounds would you expect to burn with the sooty (dark) flame?

A. B. C. D. E.

I II III IV None of them burns with a sooty flame.

10. The two compounds shown below are-------.

A. B. C. D. E.

Positional isomers Skeletal isomers Geometrical isomers Not isomers Functional group isomers

11. The chloroalkane shown below can be prepared from the reaction of

A. B. C. D. E.

n-pentane with chlorine in the dark. n-pentane with chlorine in the presence of light. 1-pentene with chlorine in the presence of light. 1-pentene with chlorine in the dark. 2-pentene with hydrogen chloride.

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12. How many mono-chlorination product(s) would be possible in the reaction of 1,3dimethylcyclobutane with chlorine in the presence of light?

A. 2 B.3 C.4 D.5 E.1 13. Give the name of major product of the following reaction.

A. B. C. D. E.

1,2-dibromo-3-methylhexane 1,2,5,6-tetrabromo-3-methylhexane 2,3,6,7-tetrabromo-1-methylhexane 2,6-dibromohexane 1,2,4,5-tetrabromo-3-methylhexane

14. Select the correct set of reagent and catalyst would be required for the following transformation?

A. B. C. D. E.

H2 + H2SO4 H2 + HgSO4 H2 + Ni H2+ Pd/charcoal/BaSO4 H2 + light

15. The major product in the reaction of one mole of 1-butyne with two moles of hydrogen chloride (HCl) will be: A. B. C. D. E.

2-chlorobutene 1,1-chlorobutane 2,2-dichlorobutane 1,2-dichlorobutane 1-chlorobutene

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16. Classify the compounds shown below in suitable set of classes.

I and II are alcohols; III and IV are 10 amines. I and II are 20 alcohols; III is a 10 amine and IV is a 20 amine. I is a 20 alcohol, II is phenol, III is an aromatic amine and IV is a 30 amine. I is a 20 alcohol, II is phenol, III is an aromatic amine and IV is a 20 amine. E. I is a 30 alcohol, II is phenol, III is an aromatic amine and IV is a 20 amine.

A. B. C. D.

17. Identify the functional groups in the compounds shown below.

A. B. C. D. E.

Aldehyde in I and ketone in II Ether in I and ketone in II Ester in I and ether in II Ether in I and ester in II Ketone and ether in I and ether in II

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SECTION B Answer all questions in this section in the space provided. (40 marks). Question One a. Give the systematic names (IUPAC) for the following compounds. [6 marks]

b. Draw the structures of compounds corresponding to the following systematic names. [4 marks] (Any form of structural representation is acceptable, (ii) the geometry of the double bond should be properly shown, subtract ½ mark if not properly shown.) (i) 3-tert-butylcyclohexene

…………………………………………………………………………………. (ii)

trans-2-hexene

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Question Two a.

For the reaction shown below write the two propagation steps involved in the reaction mechanism.[2 marks]

b.

Give the structures of the products for the reaction shown below. Indicate the major product and the minor product. [4 marks]

c.

Provide the structures of the products formed in the following reactions. [6 marks]

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Question Three a. Give the structure of the starting hydrocarbon and the reagents needed to give the indicated product. [4 marks]

b. Study the structural formula of the compound shown below. Carefully circle the functional groups in the figure and write their names. [6 marks] [Give ½ mark for identification and 1 mark for the name) .

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