18.2. Esters
A subsection of Chemistry, 9701, through 18. Carboxylic acids and derivatives
Listing 10 of 70 questions
Four esters, A, B, C and D, with the molecular formula C6H12O2 are shown in . O O O O O O O O A B C D Give the systematic name of ester A. A mixture of these esters, A, B, C and D, is analysed by gas–liquid chromatography. The chromatogram produced is shown in . The number above each peak represents the area under the peak. The area under each peak is proportional to the mass of the respective ester in the mixture. detector response ester C ester B ester A ester D time / min State what is meant by retention time. Calculate the percentage by mass of ester D in the original mixture. percentage by mass of ester D = % Separate samples of the esters, A, B, C and D, are analysed using proton (1H) NMR and carbon-13 NMR spectroscopy. Complete Table 7.1 to show the number of peaks in each NMR spectrum for esters B and C. Table 7.1 ester number of peaks in proton (1H) NMR spectrum number of peaks in carbon-13 NMR spectrum B C Identify all of the esters from A, B, C and D that have at least one triplet peak in their proton (1H) NMR spectrum. Question 7 continues on page 20. Compound F, C6H8O3, shows stereoisomerism and effervesces with Na2CO3. Compound F reacts with alkaline I2to form yellow precipitate G and compound H. Compound F reacts with LiAl H4 to form compound J, C6H12O2. Compound F reacts with SOCl 2 to form compound K, C6H7O2Cl . Compound K reacts with propan-2-ol to form compound L. Draw the structures of compounds F, G, H, J, K and L in the boxes in . F, C6H8O3 alkaline I2+ J, C6H12O2 LiAl H4 SOCl 2 K, C6H7O2Cl L propan-2-ol G H
9701_s24_qp_41
THEORY
2024
Paper 4, Variant 1
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Four esters, A, B, C and D, with the molecular formula C6H12O2 are shown in . O O O O O O O O A B C D Give the systematic name of ester A. A mixture of these esters, A, B, C and D, is analysed by gas–liquid chromatography. The chromatogram produced is shown in . The number above each peak represents the area under the peak. The area under each peak is proportional to the mass of the respective ester in the mixture. detector response ester C ester B ester A ester D time / min State what is meant by retention time. Calculate the percentage by mass of ester D in the original mixture. percentage by mass of ester D = % Separate samples of the esters, A, B, C and D, are analysed using proton (1H) NMR and carbon-13 NMR spectroscopy. Complete Table 7.1 to show the number of peaks in each NMR spectrum for esters B and C. Table 7.1 ester number of peaks in proton (1H) NMR spectrum number of peaks in carbon-13 NMR spectrum B C Identify all of the esters from A, B, C and D that have at least one triplet peak in their proton (1H) NMR spectrum. Question 7 continues on page 20. Compound F, C6H8O3, shows stereoisomerism and effervesces with Na2CO3. Compound F reacts with alkaline I2to form yellow precipitate G and compound H. Compound F reacts with LiAl H4 to form compound J, C6H12O2. Compound F reacts with SOCl 2 to form compound K, C6H7O2Cl . Compound K reacts with propan-2-ol to form compound L. Draw the structures of compounds F, G, H, J, K and L in the boxes in . F, C6H8O3 alkaline I2+ J, C6H12O2 LiAl H4 SOCl 2 K, C6H7O2Cl L propan-2-ol G H
9701_s24_qp_43
THEORY
2024
Paper 4, Variant 3
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