OCR A Jun 2016 Paper 4 Q5 (with explained solutions) |

Skip to content

OCR A Jun 2016 Paper 4 Q5

Answers available below

5 A chemistry teacher carries out an experiment to synthesise 2-aminopropan-1-ol, CH3CH(NH2)CH2OH. 12 (a) The teacher asks a university chemistry department to test the 2-aminopropan-1-ol using proton NMR spectroscopy and mass spectrometry. (i) For the 1H NMR analysis, the sample was dissolved in D2O. Complete the table to predict the 1H NMR spectrum of CH3CH(NH2)CH2OH after dissolving in D2O. 1H NMR spectrum for CH3CH(NH2)CH2OH, dissolved in D2O Chemical shift,/ ppm Relative peak area Splitting pattern (ii) The mass spectrum for CH3CH(NH2)CH2OH is shown below. [3] 100 relative intensity 80 60 40 20 peak 2 peak 1 25 50 m / z 75 100OCR 2016<br />
Give the formulae for the species responsible for peak 1 and peak 2 in the mass spectrum. 13 peak 1 peak 2 (b) The teacher synthesises 2-aminopropan-1-ol, CH3CH(NH2)CH2OH, from 2-chloropropan-1-ol, CH3CHCl CH2OH. [2] (i) State the reagents and conditions required for this synthesis.[1] (ii) The sample prepared by the teacher from 2-chloropropan-1-ol is not pure. It also contains compound D. Compound D has a molecular formula of C6H15NO2. Suggest the structure of compound D. Compound D [1]OCR 2016 Turn over<br />
(c) In a separate experiment, the chemistry teacher prepares compound E from 2-aminopropan-1-ol. 14 OH NH OH compound E (i) One of the functional groups in compound E is a phenol. Name the other functional groups in compound E.[1] (ii) Draw the structures of the two organic products formed when compound E is heated under reflux with dilute hydrochloric acid. [2] [Total: 10]OCR 2016<br />
15 BLANK PAGE PLEASE DO NOT WRITE ON THIS PAGE Turn over for the next questionOCR 2016 Turn over<br />

Show answer

F324 Question (i) 5 (a) (ii) Answer Mark 1H NMR spectrum for 2-aminopropan-1-ol Chemical shift, Relative peak (cid:71)/ppm 0.82.0 2.33.0 3.34.2 area 3 1 2 Splitting pattern doublet multiplet doublet M+ peak at 75 (peak 1) CH3CH(NH2)CH2OH+/C3H9NO+ Fragment peak at 44 (peak 2) CH3CH(NH2)+/C2H6N+ (b) (i) Ethanolic ammonia OR ammonia/NH3 AND ethanol (ii) (compound D) Mark Scheme June 2016 Guidance One mark for each correct row ALLOW (cid:71) values as a range or a value within the specified range. ALLOW (cid:71) values +/- 0.2 ppm. ALLOW a response that implies a splitting into two for a doublet etc. ALLOW sextet/hextet/six (or more than 5) as alternative to multiplet Relative peak area = CH3/3H etc. penalise once ALLOW correct structural OR displayed OR skeletal formulae OR a combination of above as long as unambiguous Positive charge is essential but ALLOW maximum of one mark if both formulae are correct AND neither species has a positive charge ALLOW ammonia in a sealed tube ALLOW dilute ethanolic ammonia/NH3 IGNORE heat ALLOW alcohol for ethanol DO NOT ALLOW any reference to water or hydroxide ions ALLOW correct structural OR displayed OR skeletal formulae OR a combination of above as long as unambiguous (cid:51)(cid:51)(cid:51) (cid:51) (cid:51) (cid:51) (cid:51) 15<br />
F324 Mark Scheme June 2016 Guidance Question (i) Alcohol (c) AND Amide/peptide (ii) Answer Mark (cid:51) (cid:51) (cid:51) Total 16 10 IGNORE phenol IGNORE hydroxyl/hydroxy IGNORE attempts to classify alcohol or amide as primary, secondary or tertiary DO NOT ALLOW hydroxide ALLOW correct structural OR displayed OR skeletal formulae OR a combination of above ALLOW correct structural OR displayed OR skeletal formulae OR combination of above as long as unambiguous ALLOW + on N or H i.e. +NH3 or NH3 + ALLOW NH3 +Cl-<br />

Question 1 2 3 4 5 6

About us | Need Help? | Feedback

Proudly powered by WordPress | Theme: Sydney by aThemes.