1 Alcohols can be prepared by the hydrolysis of haloalkanes with aqueous alkali.
i. Write an equation for the hydrolysis of 2- bromo- 2- methylpropane.
Show organic compounds as structures.
[2]
ii. A student hydrolyses a chloroalkane, RCl, a bromoalkane, RBr, and an iodoalkane, RI.
For a fair comparison, the student has chosen the same R group for each haloalkane.
Predict, with a reason, the relative rates of hydrolysis of these three haloalkanes.
[2]
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, 2 This question is about the analysis of organic compounds.
A student investigates the alkaline hydrolysis of 1-bromopropane as outlined below.
Step 1 The student adds 1-bromopropane to an excess of aqueous potassium hydroxide, KOH(aq), in a pear-
shaped flask.
Step 2 A TLC chromatogram is run using propan-1-ol and the reaction mixture.
Step 3 The reaction mixture is refluxed.
A TLC chromatogram of the reaction mixture is run every 10 minutes.
The TLC chromatograms are shown below
i. Determine the Rf value of propan–1–ol.
Show your working.
Rf = ................... [1]
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, ii. Write an equation for the alkaline hydrolysis of 1–bromopropane.
Show structures of organic compounds.
[1]
iii. A student investigates the alkaline hydrolysis of 1–chloropropane using the same method as for
1–bromopropane.
Predict, with reasons, how the appearance of the reaction mixture in the chromatogram produced after 20
minutes would be different when 1–chloropropane is used instead of 1–bromopropane.
Suggest why propan–1–ol is run alongside the reaction mixture.
[3]
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, 3 Complete the flowchart by filling in each box.
[9]
4 A student investigates the rate of hydrolysis of different iodoalkanes using aqueous silver nitrate in ethanol.
What colour of precipitate is seen?
A Brown
B Cream
C White
D Yellow
Your answer [1]
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i. Write an equation for the hydrolysis of 2- bromo- 2- methylpropane.
Show organic compounds as structures.
[2]
ii. A student hydrolyses a chloroalkane, RCl, a bromoalkane, RBr, and an iodoalkane, RI.
For a fair comparison, the student has chosen the same R group for each haloalkane.
Predict, with a reason, the relative rates of hydrolysis of these three haloalkanes.
[2]
© OCR 2025. You may photocopy this page. 1 of 56 Created in ExamBuilder
, 2 This question is about the analysis of organic compounds.
A student investigates the alkaline hydrolysis of 1-bromopropane as outlined below.
Step 1 The student adds 1-bromopropane to an excess of aqueous potassium hydroxide, KOH(aq), in a pear-
shaped flask.
Step 2 A TLC chromatogram is run using propan-1-ol and the reaction mixture.
Step 3 The reaction mixture is refluxed.
A TLC chromatogram of the reaction mixture is run every 10 minutes.
The TLC chromatograms are shown below
i. Determine the Rf value of propan–1–ol.
Show your working.
Rf = ................... [1]
© OCR 2025. You may photocopy this page. 2 of 56 Created in ExamBuilder
, ii. Write an equation for the alkaline hydrolysis of 1–bromopropane.
Show structures of organic compounds.
[1]
iii. A student investigates the alkaline hydrolysis of 1–chloropropane using the same method as for
1–bromopropane.
Predict, with reasons, how the appearance of the reaction mixture in the chromatogram produced after 20
minutes would be different when 1–chloropropane is used instead of 1–bromopropane.
Suggest why propan–1–ol is run alongside the reaction mixture.
[3]
© OCR 2025. You may photocopy this page. 3 of 56 Created in ExamBuilder
, 3 Complete the flowchart by filling in each box.
[9]
4 A student investigates the rate of hydrolysis of different iodoalkanes using aqueous silver nitrate in ethanol.
What colour of precipitate is seen?
A Brown
B Cream
C White
D Yellow
Your answer [1]
© OCR 2025. You may photocopy this page. 4 of 56 Created in ExamBuilder
