Ethene and ethane was bubbled through a cold, dilute and basic solution of potassium manganate(VII). The result can be seen as above. State the name of the test, observations and product formed that give positive result.
Baeyers' test, purple colour of potassium permanganate decolourised and brown precipitate formed and ethane-1,2-diol
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5
Name TWO reactions to prepare alkene
Dehydrohalogenation of Haloalkane, Dehydration of Alcohol
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5
The diagram shows the result obtained from a chemical test done in the lab to differentiate propane and propene. Name the chemical test and state the observations.
Reaction with bromine water/bromine in CH2Cl2. Propene: Reddish brown colour of bromine decolourised.
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5
What is the class for more stable carbocation for the formation of major product P?
Secondary
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5
Arrange the following compounds in order of increasing boiling point. 2-methylpentane, hexane, 2,3-dimethylbutane, 2,2-dimethylpentane
2-bromo-3-methylbutane reacts with alcoholic sodium hydroxide solution to give major product, B and minor product, C. Name the rule used for the formation of B and C.
Saytzeff's Rule
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5
The diagram shows one of the steps in free radical substitution mechanism. Which step does it represent?
Propagation step
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5
Which compound has higher boiling point? 2-methylpentane or cyclohexane? Give reason.
Cyclohexane. Reason: More compact and flat, larger surface area in contact within molecule, stronger IMF (vdW forces)
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5
S is formed when 2-methyl-1-butanol is heated with concentrated sulphuric acid followed by treatment with hydrogen bromide. Deduce the structure of S.
2-bromo-2-methylbutane
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5
Propanone is the only product when compound S undergo reacts with ozone, followed by Zn/H20. Determine structure S