PHYS SCIENCES P2 GR12 QP SEPT2023 English hlayiso.com

NATIONAL SENIOR CERTIFICATE GRADE 12 SEPTEMBER 2023 PHYSICAL SCIENCES P2 (CHEMISTRY) MARKS: 150 TIME: 3 hours This question paper consists of 23 pages including 4 data sheets.

2 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) INSTRUCTIONS AND INFORMATION 1. Write your full NAME and SURNAME in the appropriate spaces on the ANSWER BOOK. 2. This question paper consists of NINE questions. Answer ALL the questions in the ANSWER BOOK. 3. Start EACH question on a NEW page in the ANSWER BOOK. 4. Number the answers correctly according to the numbering system used in this question paper. 5. Leave ONE line between two sub questions, for example between QUESTION 2.1 and QUESTION 2.2. 6. You may use a non-programmable calculator. 7. You may use appropriate mathematical instruments. 8. Show ALL formulae and substitutions in ALL calculations. 9. Round off your FINAL numerical answers to a minimum of TWO decimal places. 10. Give brief motivations, discussions, et cetera where required. 11. You are advised to use the attached DATA SHEETS. 12. Write neatly and legibly. Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 3 QUESTION 1: MULTIPLE-CHOICE QUESTIONS Various options are provided as possible answers to the following questions. Choose the answer and write only the letter (A–D) next to the question numbers (1.1 to 1.10) in the ANSWER BOOK, for an example 1.11 E. 1.1 Which ONE of the following has the STRONGEST intermolecular forces? A CH3COCH3 B CH3CH2CHO C CH3CH2CH2OH D CH3CH2COOH (2) 1.2 Consider the reaction below: C2H4 + Br2 → C2H4Br2 What TYPE of reaction is represented by the above equation? A Hydration B Halogenation C Hydrogenation D Hydrohalogenation (2) 1.3 The name of the functional group of aldehydes is … A formyl. B carbonyl. C hydroxyl. D carboxyl. (2) Copyright reserved Please turn over

4 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) 1.4 Compound Q undergoes a cracking reaction to produce organic compound P and ethene, C2H4 as shown below. Compound Q → Compound P + C2H4 Compound P further undergoes a combustion reaction according to the balanced equation. P + 8 O2 → 5 CO2 + 6 H2O The IUPAC name of compound Q is … A butane. B pentane. C hexane. D heptane. (2) 1.5 The Maxwell-Boltzmann distribution curve X represents the number of molecules against kinetic energy for a certain reaction. Curve Y was obtained when one of the reaction conditions was changed. Number of particles Y X Kinetic energy Which ONE of the following factors was changed to obtain curve Y? A Pressure B Temperature C Concentration D Addition of a catalyst (2) Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 5 1.6 The following decomposition reaction is allowed to reach equilibrium: COCℓ2 (g) ⇌ CO (g) + Cℓ2 (g) Which ONE of the following graphs of [CO][Cℓ2] versus [COCℓ2] is CORRECT at equilibrium? A B [CO][Cℓ2] [CO][Cℓ2] [COCℓ2] [COCℓ2] C D [CO][Cℓ2] [CO][Cℓ2] [COCℓ2] [COCℓ2] (2) 1.7 Which ONE of the salts below can be produced by the reaction of a strong base with a weak acid? A Na2SO4 B NH4Cℓ C NaCℓ D KHCO3 (2) Copyright reserved Please turn over

6 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) 1.8 The reaction represented by the equation below reaches equilibrium. CH3COOH (aq) + H2O (ℓ) ⇌ CH3COO– (aq) + H3O+ (aq) A few drops of a concentrated solution of CH3COONa (aq) are added to the equilibrium mixture. Which ONE of the following regarding the pH and the equilibrium position is CORRECT as the reaction approaches a new equilibrium? pH Equilibrium position shifts towards the: A Increases Left B Decreases Right C Increases Right D Decreases Left (2) 1.9 The simplified diagram below represents an electrolytic cell that is used in the purification of copper (Cu). Power Source P Q Electrode P is the CATHODE of the cell. Which ONE of the following combinations regarding electrode P is correct? Reaction taking Terminal to which electrode P place at electrode P is connected A Oxidation Positive B Oxidation Negative C Reduction Positive D Reduction Negative (2) Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 7 1.10 Consider the following hypothetical spontaneous reactions: Q2+ + R → R2+ + Q P2+ + Q → P + Q2+ Which ONE of the following lists the oxidising agents in order of increasing strength? A Q2+, R2+, P2+ B R2+, Q2+, P2+ C P2+, Q2+, R2+ D P2+, R2+, Q2+ (2) [20] Copyright reserved Please turn over

8 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) QUESTION 2 (Start on a new page.) 2.1 Consider the organic compounds A to F below. A B 2-methylpent-2-ene (CH3)3COH C D CH2CH3 CH3 2,3-dimethylpentanoic acid H C C C C H H H E F H H O CH3CH2Br H C C C H H H 2.1 Write down the LETTER of the compound that: 2.1.1 Is an alkyne (1) 2.1.2 Is a haloalkane (1) 2.1.3 Has the general formula CnH2n+2O (1) 2.2 Is compound A SATURATED or UNSATURATED? Give a reason for your answer. (2) 2.3 Write down the: 2.3.1 Structural formula of compound C (2) 2.3.2 IUPAC name of compound D (2) 2.4 Is compound B a PRIMARY, SECONDARY OR TERTIARY alcohol? Give a reason for your answer. (2) 2.5 Write down the IUPAC name of a CHAIN isomer of compound B. (2) 2.6 Compound E has a functional isomer. 2.6.1 What are functional isomers? (2) 2.6.2 Write down the CONDENSED STRUCTURAL formula of the functional isomer of compound E (2) [17] Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 9 QUESTION 3 (Start on a new page.) Compounds A to C are used to investigate a factor that influences boiling point of organic compounds. The table below shows the results obtained. Compound Boiling point (°C) A Propan-1-ol 97 B Butan-1-ol 117,7 C Pentan-1-ol 138 3.1 Define boiling point. (2) 3.2 For this investigation, write down the: 3.2.1 Independent variable (1) 3.2.2 Controlled variable (1) 3.3 Name the intermolecular force that is responsible for the observed trend in boiling points. (1) 3.4 The boiling points of three branched alcohols are given below. 108 °C 129 °C 149 °C Which ONE of the three temperatures is most likely to be the boiling point of 2-methylbutan-1-ol? (1) 3.5 Fully explain your answer to QUESTION 3.4. (4) Copyright reserved Please turn over

10 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) 3.6 The graphs below represent the relationship between vapour pressure and temperature for propan-1-ol and propanal. Vapour pressure (kPa) P Q Temperature (K) 3.6.1 Define vapour pressure. (2) 3.6.2 Which curve, P or Q, represents the graph for propan-1-ol? (1) 3.6.3 Explain your answer to QUESTION 3.6.2 by referring to the TYPE of intermolecular forces. (4) [17] Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 11 QUESTION 4 (Start on a new page.) 4.1 The flow diagram below shows how compound P can be converted to organic compounds Q and R. Compound P: CH3CHBrCH2CH2CH3 Compound R Compound Q + NaBr + H2O (Alcohol) (Major product) For reaction I write down the: 4.1.1 Name of the type of substitution reaction (1) 4.1.2 IUPAC name of compound R (2) For reaction II write down: 4.1.3 One reaction condition other than heat (1) 4.1.4 The structural formula of compound Q (2) Compound R can be converted to compound Q. For the conversion of compound R to compound Q write down the: 4.1.5 Formula or name of the inorganic reagent needed (1) 4.1.6 Type of reaction (1) Copyright reserved Please turn over

12 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) 4.2 A mixture of ethanoic acid (CH3COOH) and propan-1-ol (CH3CH2CH2OH) is heated in the presence of concentrated sulphuric acid (H2SO4) in a water bath as shown below. Ethanoic acid + Propan-1-ol water + Sulphuric acid 4.2.1 Write down the name of the reaction that takes place. (1) 4.2.2 Give a reason why the reaction mixture is heated in a water bath. (1) 4.2.3 Write down the structural formula and IUPAC name of the product formed (4) [14] Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 13 QUESTION 5 (Start on a new page.) A group of learners investigate the relationship between reaction rate and concentration. They used the reaction between calcium carbonate powder, CaCO3 (s) and EXCESS hydrochloric acid solution, HCℓ (aq), at 25 °C. The balanced equation for this reaction is: CaCO3 (s) + 2 HCℓ (aq) → CaCℓ2 (aq) + H2O (ℓ) + CO2 (g) ΔH < 0 The apparatus used is illustrated below. gas syringe gas HCℓ CaCO3 The table below shows the reaction conditions for Experiments 1 and 2. EXPERIMENT CONCENTRATION VOLUME TIME TAKEN BY THE OF HCℓ OF HCℓ REACTION TO REACH (mol.dm-3) (cm3) COMPLETION (minutes) 1 0,9 50 5,28 2 1,2 50 Y 5.1 Define the term reaction rate. (2) 5.2 Name the apparatus needed for this investigation that is not shown in the sketch above. (1) 5.3 Give a reason why the temperature of the reaction mixtures does not remain constant during the reactions. (1) 5.4 Will time Y for experiment 2 be LONGER or SHORTER than 5,28 minutes? (1) 5.5 Explain your answer to QUESTION 5.4 by referring to the collision theory. (2) Copyright reserved Please turn over

14 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) 5.6 In experiment 1, exactly 250 cm3 of CO2 is produced in 5,28 minutes. 5.6.1 Calculate the average rate of production of CO2 in cm3·min-1 (3) Shortly after the reaction in experiment 1 is completed, the flask is sealed tightly and it is found that 100 cm3 of CO2 has escaped out of the flask. 5.6.2 Calculate of mass of CO2 remaining in the flask after the flask is sealed. Take the molar volume of CO2 at 25 °C to be 25 000 cm3·mol-1. (4) 5.7 In experiment 3 the learners now add 50 cm3 of EXCESS ethanoic acid (C2H4O2) solution with a concentration of 0,9 mol·dm -3 to CaCO3 powder at 25 °C and compare the results to those of experiment 1. The graph of volume of CO2 against time for the two experiments is shown below. Volume of CO2 Q P (cm3) Time (minutes) 5.7.1 Which graph P or Q represents the results of experiment 3? (1) 5.7.2 Explain your answer to QUESTION 5.7.1. (2) 5.7.3 How does the amount of CaCO3 used in experiment 1 compare to the amount of CaCO3 used in experiment 3? Choose from LARGER THAN, SMALLER THAN or EQUAL TO. Give a reason for your answer. (2) [19] Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 15 QUESTION 6 (Start on a new page.) 6.1 Sulphur trioxide (SO3) gas is injected into an empty container which is then sealed. The following reaction takes place inside the container: 2 SO3 (g) ⇌ 2 SO2 (g) + O2 (g) The graph below shows the changes in the reaction rates against time for the first 20 minutes. Reaction rate (mol·dm-3·min- 1) 0 10 15 20 Time (minutes) 6.1.1 Write down the meaning of the double arrow “⇌” in the equation. (1) 6.1.2 What is represented by the horizontal section of the graph between t = 10 minutes and t = 15 minutes (1) At t = 15 minutes the temperature of the reaction mixture in the container was changed. 6.1.3 Was the container COOLED or HEATED at t = 15 minutes? (1) 6.1.4 Is the forward reaction EXOTHERMIC or ENDOTHERMIC? (1) 6.1.5 Explain your answer to QUESTION 6.1.4 by referring to Le Chatelier’s principle. (2) Copyright reserved Please turn over

16 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) After 20 minutes the pressure inside the reaction container is increased by decreasing the volume at constant temperature. 6.1.6 Redraw the graph below and indicate the effect that the increase in pressure will have on the reaction rate up until a new equilibrium is established. GRAPH OF RATE VERSUS TIME Reaction rate (mol·dm-3·min-1) 20 Time (minutes) (2) 6.2 Carbon (C) and carbon dioxide (CO2) are mixed in an empty 2 dm3 container which is then sealed. The following balanced equation represents the reaction that reaches equilibrium in the container at 700 °C. C (s) + CO2 (g) ⇌ 2 CO (g) At equilibrium, it is found that the concentration of CO2 is 0,05 mol.dm-3 and 0,4 moles of C (s) are present. The equilibrium constant for this reaction at 700 °C is 0,05. Calculate the percentage of carbon that has reacted. (8) [16] Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 17 QUESTION 7 (Start on a new page.) 7.1 Consider the ionisation of oxalic acid, H2C2O4 (aq), represented by the following balanced equation: H2C2O4 (aq) + H2O (ℓ) ⇌ HC2O4 – (aq) + H3O+ (aq) The concentration of EACH of the substances found in 0,1 mol·dm-3 solution of H2C2O4 at equilibrium is given in the table below. Substances H2C2O4 HC2O4 – H3O+ Concentration 0,046 0,054 0,054 (mol·dm-3) 7.1.1 Define an acid according to the Lowry-Brønsted theory. (2) 7.1.2 Write down the formula of a base in the above reaction other than H2O. (1) 7.1.3 Is oxalic acid (H2C2O4) a STRONG or a WEAK acid? (1) 7.1.4 Explain your answer to QUESTION 7.1.3 by referring to the data in the table. (2) 7.2 A concentrated sodium hydroxide solution, NaOH(aq), is diluted with water to one tenth of its original concentration. Exactly 35 cm3 of the dilute sodium hydroxide solution is mixed with 25 cm3 of hydrochloric acid solution, HCℓ (aq) of concentration 0,1 mol·dm-3 in a flask. A neutralisation reaction occurs in the flask according to the balanced equation: HCℓ (aq) + NaOH (aq) → NaCℓ (aq) + H2O (ℓ) 7.2.1 Calculate the initial number of moles of HCℓ in the flask. (3) The pH of the final solution is 12. Calculate the CONCENTRATION of the: 7.2.2 Hydroxide ions (OH-) in the final solution (4) 7.2.3 Concentrated sodium hydroxide (NaOH) (6) [19] Copyright reserved Please turn over

18 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) QUESTION 8 (Start on a new page.) A galvanic cell is set up under standard conditions. One half cell consists of a silver plate, Ag, in an aqueous solution of AgNO3, while the other half cell consists of an inert platinum plate in an aqueous solution containing, Fe 2+ and Fe3+, as shown in the simplified diagram below. V Ag Pt AgNO3 (aq) Fe2+ and Fe3+ 8.1 Write down the energy change that takes place when this cell is in operation. (2) 8.2 For this galvanic cell, write down the: 8.2.1 Oxidation half-reaction (2) 8.2.2 Cell notation (3) 8.2.3 TWO standard conditions for the Fe2+, Fe3+ half cell (2) 8.3 Calculate the initial emf of this cell. (4) 8.4 What would happen to the emf calculated in QUESTION 8.3, if a solution of NaCℓ were to be used as a salt bridge in the cell under standard conditions? Write down only INCREASES, DECREASES or REMAINS THE SAME. (1) 8.5 Explain your answer to QUESTION 8.4. (2) [16] Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 19 QUESTION 9 (Start on a new page.) The electrolytic cell shown below is used for the electrolysis of CuCℓ2 solution. A B CuCℓ2 (aq) A and B are carbon electrodes. 9.1 Define electrolysis. (2) 9.2 Is the process of electrolysis EXOTHERMIC of ENDOTHERMIC? (1) 9.3 Write down the half reaction that occurs at electrode B. 0,369 g of Cu is deposited on the cathode in 27 minutes. (2) 9.4 Calculate the electrical current used during this process. (7) [12] TOTAL: 150 Copyright reserved Please turn over

20 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) NATIONAL SENIOR CERTIFICATE NASIONALE SENIOR SERTIFIKAAT DATA FOR PHYSICAL SCIENCES GRADE 12 PAPER 2 (CHEMISTRY) GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 12 VRAESTEL 2 (CHEMIE) TABLE 1: PHYSICAL CONSTANTS/TABEL 1: FISIESE KONSTANTES NAAM/NAME SIMBOOL/SYMBOL WAARDE/VALUE Standard pressure Standaarddruk p 1,013 × 105 Pa Molar gas volume at STP Vm 22,4 dm3∙mol-1 Molêre gasvolume teen STD Standard temperature Tθ 273 K Standaardtemperatuur Charge on electron Lading op elektron e -1,6 × 10-19 C Avogadro’s constant NA 6,02 × 1023 mol-1 Avogadro se konstante TABLE 2: FORMULAE/TABEL 2: FORMULES m n m n = M or/of c = V or/of c = MV pH= -log[H3O+] N ca Va na Kw = [H3O+][OH-] = 1x10-14 at /by 298K n= N or/of = A cb Vb nb V n= V m Eθcell = Eθcathode – Eθanode / Eθsel = Eθkatode – Eθanode Eθcell = Eθreduction – Eθoxidation / Eθsel = Eθreduksie – Eθoksidasie Eθcell = Eθoxidising agent – Eθreducing agent / Eθsel = Eθoksideermidde l– Eθreduseermiddel Q Q q =IΔt n= e or/of n = q e Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 21 TABLE 3: THE PERIODIC TABLE OF ELEMENTS/TABEL 3: DIE PERIODIEKE TABEL VAN ELEMENTE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 (I) (II) Atoomgetal (III) (IV) (V) (VI) (VII) (VIII) KEY/ SLEUTEL Atomic number 1 2 H He 2,1 1 29 4 Elektronegatiwiteit Simbool 3 4 Electronegativity 1,9 Cu Symbol 5 6 7 8 9 10 Li Be 63,5 B C N O F Ne 1,0 1,5 2,0 2,5 3,0 3,5 4,0 7 9 11 12 14 16 19 20 11 12 13 14 15 16 17 18 Na Mg Benaderde relatiewe atoommassa Aℓ Si P S Cℓ Ar 0,9 1,2 Approximate relative atomic mass 1,5 1,8 2,1 2,5 3,0 23 24 27 28 31 32 35,5 40 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 0,8 1,0 1,3 1,5 1,6 1,6 1,5 1,8 1,8 1,8 1,9 1,6 1,6 1,8 2,0 2,4 2,8 39 40 45 48 51 52 55 56 59 59 63,5 65 70 73 75 79 80 84 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 0,8 1,0 1,2 1,4 1,8 1,9 2,2 2,2 2,2 1,9 1,7 1,7 1,8 1,9 2,1 2,5 86 88 89 91 92 96 101 103 106 108 112 115 119 122 128 127 131 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tℓ Pb Bi Po At Rn 0,7 133 0,9137 139 1,6 179 181 184 186 190 192 195 197 201 1,8204 1,8 207 1,9 209 2,0 2,5 87 88 89 Fr Ra Ac 0,7 0,9226 58 59 60 61 62 63 64 65 66 67 68 69 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 140 141 144 150 152 157 159 163 165 167 169 173 175 90 91 92 93 94 95 96 97 98 99 100 101 102 103 Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr 232 238 Copyright reserved Please turn over

22 PHYSICAL SCIENCES P2 (EC/SEPTEMBER 2023) TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD REDUKSIEPOTENSIALE Half-reactions/Halfreaksies Eθ (V) F2(g) + 2e− ⇌ 2F− + 2,87 Co3+ + e− ⇌ Co2+ + 1,81 H2O2 + 2H +2e + − ⇌ 2H2O +1,77 − MnO 4 + 8H+ + 5e− ⇌ Mn 2+ + 4H2O + 1,51 Cℓ2(g) + 2e− ⇌ 2Cℓ − + 1,36 2− Cr2O 7 + 14H+ + 6e− ⇌ 2Cr3+ + 7H2O + 1,33 O2(g) + 4H+ + 4e− ⇌ 2H2O + 1,23 MnO2 + 4H+ + 2e− ⇌ Mn2+ + 2H2O + 1,23 Pt2+ + 2e− ⇌ Pt + 1,20 Br2(ℓ) + 2e − ⇌ 2Br − + 1,07 − ⇌ NO(g) + 2H2O + 0,96 Increasing reducing ability/Toenemende reduserende vermoë NO 3 + 4H+ + 3e− Increasing oxidising ability/Toenemende oksiderende vermoë Hg2+ + 2e− ⇌ Hg(ℓ) + 0,85 + Ag + e − ⇌ Ag + 0,80 − NO 3 + 2H+ + e− ⇌ NO2(g) + H2O + 0,80 Fe 3+ +e − ⇌ Fe 2+ + 0,77 O2(g) + 2H+ + 2e− ⇌ H2O2 + 0,68 I2 + 2e − ⇌ 2I − + 0,54 Cu+ + e− ⇌ Cu + 0,52 SO2 + 4H+ + 4e− ⇌ S + 2H2O + 0,45 2H2O + O2 + 4e − ⇌ 4OH − + 0,40 Cu 2+ + 2e − ⇌ Cu + 0,34 2− SO 4 + 4H+ + 2e− ⇌ SO2(g) + 2H2O + 0,17 Cu2+ + e− ⇌ Cu+ + 0,16 Sn 4+ + 2e − ⇌ Sn 2+ + 0,15 S + 2H+ + 2e− ⇌ H2S(g) + 0,14 2H+ + 2e− ⇌ H2(g) 0,00 Fe 3+ + 3e − ⇌ Fe − 0,06 Pb2+ + 2e− ⇌ Pb − 0,13 Sn2+ + 2e− ⇌ Sn − 0,14 Ni2+ + 2e− ⇌ Ni − 0,27 Co 2+ + 2e − ⇌ Co − 0,28 Cd2+ + 2e− ⇌ Cd − 0,40 Cr3+ + e− ⇌ Cr2+ − 0,41 Fe2+ + 2e− ⇌ Fe − 0,44 Cr 3+ + 3e − ⇌ Cr − 0,74 Zn2+ + 2e− ⇌ Zn − 0,76 2H2O + 2e− ⇌ H2(g) + 2OH− − 0,83 Cr2+ + 2e− ⇌ Cr − 0,91 Mn 2+ + 2e − ⇌ Mn − 1,18 Aℓ3+ + 3e− ⇌ Aℓ − 1,66 Mg2+ + 2e− ⇌ Mg − 2,36 + Na + e − ⇌ Na − 2,71 Ca2+ + 2e− ⇌ Ca − 2,87 Sr2+ + 2e− ⇌ Sr − 2,89 Ba2+ + 2e− ⇌ Ba − 2,90 Cs+ + e- ⇌ Cs - 2,92 + K +e − ⇌ K − 2,93 Li+ + e− ⇌ Li − 3,05 Copyright reserved Please turn over

(EC/SEPTEMBER 2023) PHYSICAL SCIENCES P2 23 TABLE 4B: STANDARD REDUCTION POTENTIALS TABEL 4B: STANDAARD REDUKSIEPOTENSIALE Half-reactions/Halfreaksies Eθ (V) Li+ + e− ⇌ Li − 3,05 K+ + e− ⇌ K − 2,93 Cs+ + e− ⇌ Cs − 2,92 Ba2+ + 2e− ⇌ Ba − 2,90 Sr2+ + 2e− ⇌ Sr − 2,89 Ca2+ + 2e− ⇌ Ca − 2,87 + Na + e − ⇌ Na − 2,71 Mg2+ + 2e− ⇌ Mg − 2,36 Aℓ3+ + 3e− ⇌ Aℓ − 1,66 Mn2+ + 2e− ⇌ Mn − 1,18 Cr2+ + 2e− ⇌ Cr − 0,91 Increasing reducing ability/Toenemende reduserende vermoë 2H2O + 2e− ⇌ H2(g) + 2OH− − 0,83 Increasing oxidising ability/Toenemende oksiderende vermoë Zn2+ + 2e− ⇌ Zn − 0,76 3+ Cr + 3e − ⇌ Cr − 0,74 Fe2+ + 2e− ⇌ Fe − 0,44 Cr3+ + e− ⇌ Cr2+ − 0,41 Cd2+ + 2e− ⇌ Cd − 0,40 Co2+ + 2e− ⇌ Co − 0,28 Ni2+ + 2e− ⇌ Ni − 0,27 2+ Sn + 2e − ⇌ Sn − 0,14 Pb2+ + 2e− ⇌ Pb − 0,13 Fe3+ + 3e− ⇌ Fe − 0,06 2H+ + 2e− ⇌ H2(g) 0,00 S + 2H+ + 2e− ⇌ H2S(g) + 0,14 4+ Sn + 2e − ⇌ Sn 2+ + 0,15 Cu2+ + e− ⇌ Cu+ + 0,16 2− SO 4 + 4H+ + 2e− ⇌ SO2(g) + 2H2O + 0,17 Cu2+ + 2e− ⇌ Cu + 0,34 2H2O + O2 + 4e− ⇌ 4OH− + 0,40 SO2 + 4H + 4e + − ⇌ S + 2H2O + 0,45 + Cu + e − ⇌ Cu + 0,52 I2 + 2e− ⇌ 2I− + 0,54 O2(g) + 2H+ + 2e− ⇌ H2O2 + 0,68 Fe3+ + e− ⇌ Fe2+ + 0,77 − NO 3 + 2H+ + e− ⇌ NO2(g) + H2O + 0,80 Ag+ + e− ⇌ Ag + 0,80 2+ Hg + 2e − ⇌ Hg(ℓ) + 0,85 − NO 3 + 4H+ + 3e− ⇌ NO(g) + 2H2O + 0,96 Br2(ℓ) + 2e − ⇌ 2Br − + 1,07 Pt2+ + 2 e− ⇌ Pt + 1,20 MnO2 + 4H+ + 2e− ⇌ Mn2+ + 2H2O + 1,23 O2(g) + 4H+ + 4e− ⇌ 2H2O + 1,23 2− Cr2O 7 + 14H+ + 6e− ⇌ 2Cr3+ + 7H2O + 1,33 Cℓ2(g) + 2e− ⇌ 2Cℓ− + 1,36 − MnO 4 + 8H+ + 5e− ⇌ 2+ Mn + 4H2O + 1,51 H2O2 + 2H +2 e + − ⇌ 2H2O +1,77 Co3+ + e− ⇌ Co2+ + 1,81 F2(g) + 2e− ⇌ 2F− + 2,87 Copyright reserved