Green Road Trial Sem 3 2022 Quastion
Green Road Trial Sem 3 2022 Quastion
Green Road Trial Sem 3 2022 Quastion
Class : …………
Instructions to candidates:
Section B
16
17
Section C
Total
Section A
1 2 3 4 5 6 7 8
9 10 11 12 13 14 15
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_____________________ _____________________
(Annie Afzan bt. Ariffin) (Chai Kim Lian)
Section A [15 marks]
2. The following mechanism shows the reaction between methane and bromine in the presence of
ultraviolet light.
Uv light
Step 1 : Br2 2 Br•
Step 2 : Br• + CH4 → HBr + •CH3
Step 3 : •CH3 + Br2 → CH3Br + Br•
Which of the following statements about the above reaction could be correct?
A The above reaction can be carried out in the dark at room temperature
B The above reaction can be initiated by adding methyl radical in the dark.
C The only product formed is CH3Br.
D The above reaction stops at step III.
3. When two organic compounds X and Y from two different homologous series are burnt
separately in an excess of oxygen at 150 ˚C and ordinary pressure, the volume of carbon dioxide
is the same as that of water vapour formed. X and Y could be
A B C D
X alkane alkane alkene cycloalkane
Y alkene aldehyde ketone alkene
4. Which property does benzene have as a consequence of the delocalisation of electrons in the
benzene molecule?
A Benzene is a good conductor of electricity.
B The carbon-carbon bond lengths are between those of C-C bonds and C=C bonds.
C Addition reaction of benzene take place more easily than substitution.
D Substitution in benzene takes place at one particular carbon atom.
5 A liquid P decolourised bromine water and formed a white precipitate with aqueous silver
nitrate. Y could be
I CH2=CHCH2Cl III CH2CH2Cl
II CH2Cl IV
CH2CH3
Cl
A I and II only correct C II and III only correct
B I and IV only correct D III and IV only correct
6 Which of the following reagents can react with ethanol and phenol?
A ethanoic acid C ethanoyl chloride
B aqueous bromine D aqueous sodium hydroxide
7 A compound R reacts with phosphorus pentachloride to give off an acidic gas. R also reacts
with S reagent to produce a compound T which gives a grey precipitate with Tollens’ reagent.
Which of the following combinations could apply to R, S and T?
R S T
+
A CH3CH2CH2OH KMnO4/H CH3CH2CHO
B CH3CH(OH)CH3 KMnO4/H+ CH3COCH3
+
C C6H5CH2OH KMnO4/H C6H5COCH3
+
D CH3CH2COOH K2Cr2O7/H CH3CH2CHO
13 In many countries, plastic waste is collected separately and sorted. Some of this is incinerated
to provide heat for power stations. Why is pvc; polyvinyl chloride; removed from any waste
that is to be incinerated?
A It can be melted down and re-used.
B Its combustion products are harmful.
C It destroys the ozone layer.
D It does not burn easily.
15 Plastic can be classified as thermoplastic and thermosetting plastic based on its thermal
properties. Which is a thermosetting plastic?
A Bakelite B Perspex
C Polystyrene D Polyvinyl chloride
Section B [15 marks]
Answer all questions in this section.
16 Acetaminophen is a drug used to relieve pain and fever. The structural formula of
acetaminophen is shown below:
HO N – C – CH3
H O
……………………………………………………………………………………………..
……………………………………………………………………………………………..
c) Write the chemical equation when acetaminophen is heated with aqueous sodium
hydroxide solution. [1]
………………………………………………………………………………………………
d) Write the structural formulae of the products formed and state the observations when
acetaminophen reacts with the following reagents. [4]
i. Bromine water; ii. LiAlH4 followed by HCl(aq);
Observation: Observation:
17 Tryptophan is a compound used by human body to make protein. The reactions of tryptophan
are shown in the reaction scheme below.
Reaction P : ……………………………………………………………………………….
Reaction Q : ……………………………………………………………………………….
ii) pH = 9 :
d) Tryptophan forms isomers which rotate the plane polarised light. Deduce and draw the
structures of the isomers of tryptophan. [3]
…………………………………………………………………………………………………
…………………………………………………………………………………………………
…………………………………………………………………………………………………
Section C [30 marks]
Answer any 2 questions in this section.
18
a) Para-aminobenzoic acid, PABA, is commonly found in human body, which can be generated
from bacteria found in intestinal tract such as E.Coli. Propose a reaction scheme of how PABA can be
prepared from benzene. [8]
b) The structural formulae of three hydroxyl compounds are shown below.
OH OH H3 C OH
Compare and explain the acidity between cyclohexanol, phenol and 4-methylphenol. [7]
19 A hydrocarbon, A, produces two isomers of B and D, C3H6O, when reacts with ozone followed
by hydrolysis. When heated with dilute sulphuric acid, compound A produces a major product, E.
compound E does not give observable change when reacts with acidified potassium manganate(VII)
solution. When compound G reacts with Mg in dry ether followed with compound D and is hydrolysed,
compound E is formed. Compound G contains 45.9% by mass of carbon, 45.2% of chlorine and 8.9%
of hydrogen.
a) Determine the empirical formula of compound G. [2]
b) Identify the structural formulae of compounds A, B, D, E and G. [5]
c) Suggest a chemical test to distinguish between compound B and D. [3]
d) Write the reaction mechanism when compound G is refluxed with ethanolic potassium cyanide.
[5]
20 An alcohol J reacts with hot concentrated sulphuric acid and gives compounds K and L, C 9H10,
which are isomers of each other. Both compounds K and L react with bromine, where K forms
compound N whereas compound L reacts to give compound M. Compound L gives effervescence when
treated with hot acidified potassium manganate(VII) solution. While compound J gives yellow
precipitate when reacts with alkaline iodine solution. Compound P is produced when compound J reacts
with copper heated at 400 ˚C.
a) Draw the structural formulae of compounds J, K, L, M, N and P. [6]
b) Compound K also isomeric with compound Q. Explain the type of isomerism shown by
compound K and Q. [3]
c) Write the reaction mechanism for the formation of compound M from compound L. [4]
d) Write the chemical equations for the formation of yellow precipitate from compound J and
effervescence from compound L. [2]