Physical Sciences Grade 12 P2 KZN Prelim 2024 Question Paper

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE GRADE 12 PHYSICAL SCIENCES P2 (CHEMISTRY) PREPARATORY EXAMINATION SEPTEMBER 2024 MARKS : 150 TIME : 3 Hours This question paper consists of 17 pages and 4 data sheets. Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 2 September 2024 Preparatory Examination NSC INSTRUCTIONS AND INFORMATION 1. Write your name 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 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

Downloaded from hlayiso.com Physical Sciences/P2 3 September 2024 Preparatory Examination NSC QUESTION 1: MULTIPLE-CHOICE QUESTIONS Four options are provided as possible answers to the following questions. Each question has only ONE correct answer. Choose the answer and write only the letter (A–D) next to the question number (1.1–1.10) in the ANSWER BOOK, for example 1.11 E. 1.1 Which ONE of the following general formulae represents alkenes? A CnH2n B CnH2n – 1 C CnH2n + 2 D CnH2n – 2 (2) 1.2 Which ONE of the following compounds has the HIGHEST vapour pressure? A CH3CH2C(CH3)2CH3 B CH3CH2CH(CH3)CH2CH3 C CH3CH2CH2CH2CH2CH3 D CH3CH(CH3)CH2CH2CH3 (2) 1.3 A simple reaction scheme is shown below: HBr(g) reflux with C3H6 F G + NaBr NaOH(aq) The formula for G is . . . A CH3CH2COOH B CH3CHOHCH3 C CH3CHBrCH2OH D CH3CHOHCH2Br (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 4 September 2024 Preparatory Examination NSC 1.4 The graph below represents the energy profile for a hypothetical reaction. +50 Potential energy (kJ) +20 0 Reaction Co-ordinate -66 Which ONE of the following combinations for the Activation Energy of the reverse reaction and Heat of Reaction of the reverse reaction can be correctly concluded from the above energy profile? Activation Energy (kJ) Heat of Reaction (kJ) A -20 +86 B 30 +86 C -116 -86 D +116 +86 (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 5 September 2024 Preparatory Examination NSC 1.5 Curves X and Y, show the volume-time relationship for the following reaction: Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g) Curves X and Y are produced under the SAME conditions. However, curve Y, is produced by adding an aqueous solution of copper sulphate to the reaction mixture. Y Volume of H2(g) X 0 time (s) Which ONE of the following correctly explains why curve Y is different from curve X? A Copper ions act as a catalyst. B The concentration of the sulphate ions increases. C Zinc displaces the copper from the copper sulphate. D The change in the concentration of sulphuric acid decreases per unit (2) time. 1.6 Dihydrogen sulphide (H2S), dissolves in water according to the following equation: H2S + 2H2O ⇌ S2- + 2H3O+ When equilibrium is reached, a solution of hydrochloric acid (HCℓ) is added to the solution containing dihydrogen sulphide. Which ONE of the following statements is correct? A The concentration of the sulphide ions increases. B The concentration of the sulphide ions decreases. C The concentration of the sulphide ions remains unchanged. D The extent of the ionisation of the hydrochloric acid will increase. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 6 September 2024 Preparatory Examination NSC 1.7 The beakers, X and Y, below contain equal volumes of an aqueous solution of HCℓ and an aqueous solution of H3PO4 respectively. HCℓ(aq) H3PO4(aq) X Y How will the concentration of the hydronium ions, (H3O+) and the pH for the two solutions compare if both solutions have the same concentration? A The concentration of the hydronium ions and pH of Y is equal to the concentration of the hydronium ions and pH of X. B The concentration of the hydronium ions and pH of Y is less than the concentration of the hydronium ions and pH of X. C The concentration of the hydronium ions of Y is greater than the concentration of the hydronium ions of X, while the pH of Y is less than the pH of X. D The concentration of the hydronium ions of Y is greater than the concentration of the hydronium ions of X, while the pH of Y is greater than the pH of X. (2) 1.8 The following equilibrium exists in pure water at 25 °C. 2H2O(ℓ) ⇌ H3O+(aq) + OH-(aq) ΔH > 0 At this temperature, the pH = 7 and Kw = 1 x 10 -14 The temperature of the water is increased to 90 °C. Which ONE of the following is TRUE at the new temperature? A pH = 7 B [H3O+] = [OH-] C [H3O+] = 10-7 mol.dm-3 D [H3O+][OH-] = 1 x 10-14 (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 7 September 2024 Preparatory Examination NSC 1.9 A galvanic cell is constructed using lead (Pb) and magnesium (Mg) electrodes. The electrons flow from the . . . A Pb half-cell to the Mg half-cell through the salt bridge. B Pb half-cell to the Mg half-cell through the wire. C Mg half-cell to the Pb half-cell through the salt bridge. D Mg half-cell to the Pb half-cell through the wire. (2) 1.10 Which ONE of the half-reactions below will be the MAIN reaction at the CATHODE during the electrolysis of CONCENTRATED NaCℓ (aq)? A 2Cℓ-(aq) → Cℓ2(g) + 2e- B Na+(aq) + e- → Na(s) C 2H2O(ℓ) + 2e- → H2(g) + 2OH-(aq) D 2H2O(ℓ) → O2(g) + 4H+(aq) + 4e- (2) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 8 September 2024 Preparatory Examination NSC QUESTION 2 (Start on a new page.) The letters A to F in the table below represent six organic compounds. H H │ │ H ― C ― C ― H │ H H H H H │ │ │ │ H ― C ― C ― C ― C ≡ C ― C ― C ― H A │ │ │ H H H H ― C ― H H ― C ― H │ │ H H B C3H8O C C4H8O D CH3CH(CH3)COCH2CH3 H │ H ― C ― H H H H H │ │ │ │ H ― C ― C ― C ― C ═ C ― C ― H │ │ │ │ H H H H E H ― C ― H │ H H H H Br Br H │ │ │ │ │ │ H ― C ― C ― C ― C ― C ― C ― H │ │ │ │ │ H H H H H F H ― C ― H │ H ― C ― H │ H Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 9 September 2024 Preparatory Examination NSC 2.1 Write down the IUPAC name of the compound: 2.1.1 A (3) 2.1.2 F (2) 2.2 Write down the: 2.2.1 STRUCTURAL formula of the FUNCTIONAL GROUP of compound D. (2) 2.2.2 Name of the homologous series to which compound B belongs. (1) 2.2.3 Letter of ONE compound that is unsaturated. Give a reason for the answer. (2) 2.3 Write down the STRUCTURAL FORMULAE of the ISOMERS of compound C. (4) 2.4 Name the type of isomers shown in question 2.3 (1) [15] QUESTION 3 (Start on a new page.) Learners use three primary alcohols P, Q and R with the same molecular formula to investigate ONE of the factors which influences boiling points of organic compounds. The table below shows the results obtained. ALCOHOL BOILING POINT (°C) P 108 Q 149 R 129 Take the atmospheric pressure as 100kPa. 3.1 Define vapour pressure. (2) 3.2 Write down the vapour pressure of alcohol Q at 149 °C. Explain the answer. (2) 3.3 Which alcohol P or R has a higher vapour pressure than alcohol Q. Write down a reason for the answer. (2) 3.4 Name the independent variable for this investigation. (1) 3.5 Use the results given in the table to fully explain how the independent variable influences the boiling point of the alcohols. (4) 3.6 The molecular mass of alcohol Q is 88 g.mol-1. Write down the structural formula for alcohol P. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 10 September 2024 Preparatory Examination NSC 3.7 The curves A, B and C in random order represents the graph of vapour pressure versus temperature for the alcohols P, Q and R on the same set of axes. 3.7.1 Write down the value of the temperature represented by the letter T on the graph. (1) 3.7.2 Explain the answer to question 3.7.1 by referring to both the graph and the information provided in the table. (3) [18] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 11 September 2024 Preparatory Examination NSC QUESTION 4 (Start on a new page.) In the flow diagram below, 1, 2, 3, and 4 represent organic reactions. A, B, C, D and E represent organic compounds. Compound E 3 Compound D 4 Compound A Compound B 1 (Major product) 2 Compound C CH3CHOH(CH2)2CH3 4.1 Compound B belongs to a homologous series that has a general formula CnH2n + 2 4.1.1 Name the type of addition reaction that takes place. (1) 4.1.2 Apart from heat, write down ONE other reaction condition for this reaction. (1) 4.2 Compound C is formed when compound A is treated with HBr in reaction 1. Reaction 1 is classified as an ADDITION reaction. Write down: 4.2.1 The structural formula of compound A. (2) 4.2.2 TWO terms that describe reaction 2. (2) 4.2.3 TWO properties of the base used in reaction 2. (2) 4.3 With the aid of a catalyst, compound A can be converted directly to compound D without the formation of the intermediate compound C. Write down the: 4.3.1 Name or formula of the inorganic REACTANT needed for this direct conversion (1) 4.3.2 Name or formula of a catalyst that can be used (1) 4.3.3 Type of addition reaction that takes place. (1) 4.4 In reaction 4, compound B is treated with concentrated sodium hydroxide, and the mixture is heated. 4.4.1 Name the type of reaction that takes place. (1) 4.4.2 Using molecular formulae, write a balanced equation for reaction 4. (3) [15] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 12 September 2024 Preparatory Examination NSC QUESTION 5 (Start on a new page.) Learners use the reaction of powdered calcium carbonate with EXCESS dilute hydrochloric acid of equal volumes and concentrations, to investigate the rate of a chemical reaction. The balanced equation for the reaction is: CaCO3(s) + 2HCℓ(aq) → CaCℓ2(aq) + CO2(g) + H2O(ℓ) ΔH < 0 REACTION Mass of CaCO3 in grams I 22,57 Pure II 22,57 Impure The graph below shows one of the results obtained. Volume of carbon dioxide gas (dm3) 6 5 4 3 2 1 0 1 2 3 4 5 6 7 8 9 Time in minutes The molar gas volume is 25,7 dm3. 5.1 Define the term reaction rate. (2) 5.2 It is observed that once the reaction starts, the initial rate of the reaction increases. Use the collision theory to fully explain the increase in the initial (3) rate of the reaction. 5.3 Calculate the average rate at which carbon dioxide gas is produced for the interval 1 minute to 3 minutes. (3) 5.4 How will the average rate at which carbon dioxide gas is produced for the interval 4 minutes to 6 minutes compare with the interval 1 minute to 3 minutes? Choose from GREATER THAN, EQUAL TO, or LESS THAN. Explain the answer using the collision theory. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 13 September 2024 Preparatory Examination NSC 5.5 Perform the necessary calculations to explain whether the graph represents the results of reaction I or reaction II. (7) 5.6 Sketch the above graph in your answer book and label it as F. On the same set of axes sketch the curve that would be obtained for the other reaction. Label it G. (2) [20] QUESTION 6 (Start on a new page.) Consider the balanced equation for a reaction that takes place in a sealed 2 dm3 container. 2SO2(g) + O2(g) ⇌ 2SO3(g) 6.1 What information in the equation indicates that the above reaction is (1) reversible? 6.2 State Le Chatelier’s Principle. (2) The pressure in the container is INCREASED without changing the temperature. 6.3 Will the number of moles of SO3(g) produced, INCREASE or DECREASE? Use Le Chatelier’s Principle to explain the answer. (3) The reaction represented in the equation above reaches equilibrium at a temperature T in the same sealed 2 dm3 container. On analysis of the equilibrium mixture, it is found that 0,6 mol of SO2(g), 0,5 mol of O2(g), and 0,4 mol of SO3(g) are present in the container. The container's temperature is NOW decreased, and the reaction is allowed to reach equilibrium for the second time. When a new equilibrium is established, it is found that there are 25,6 g of SO2(g) present in the container. 6.4 Is the forward reaction EXOTHERMIC or ENDOTHERMIC? Use Le Chatelier’s Principle to explain the answer. (4) 6.5 Calculate the equilibrium constant for this reaction at the NEW temperature. (8) [18] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 14 September 2024 Preparatory Examination NSC QUESTION 7 (Start on a new page.) 7.1 The hydrogen carbonate ion, (HCO3 -), is an ampholyte. 7.1.1 Define an ampholyte. (2) 7.1.2 Write a balanced equation to show the reaction that occurs when the hydrogen carbonate ion reacts with water. (3) 7.2 A flask contains 20 cm3 of dilute sulphuric acid, H2SO4(aq) of concentration 0,15 mol.dm-3. 7.2.1 Calculate the pH of the dilute sulphuric acid. (3) To obtain a final pH of 12,96 a learner adds 30 cm 3 of dilute sodium hydroxide, NaOH(aq) of concentration 0,25 mol.dm -3 to the flask according to the following balanced equation: H2SO4(aq) + 2 NaOH(aq) → Na2SO4(aq) + 2 H2O(ℓ) An unknown volume of dilute barium hydroxide (Ba(OH) 2) of concentration 0,10 mol.dm-3 is then added to the flask to obtain the pH of 12,96. Assume that the volumes are additive and that both sodium hydroxide, NaOH(aq) and barium hydroxide (Ba(OH) 2) are strong bases. 7.2.2 Calculate the volume of barium hydroxide that was added. (8) [16] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 15 September 2024 Preparatory Examination NSC QUESTION 8 (Start on a new page.) The table below shows a half-cell A and an unknown half-cell B used to assemble an electrochemical cell under STANDARD CONDITIONS. Half-cell A Ag+(aq) Ag(s) Half-cell B Unknown The following observations were made while the cell was in operation: (I) Cations from the salt bride move into the electrolyte of half-cell A. (II) The initial emf of the cell is 0,03 V. 8.1 Calculate the Eᶿ value for half-cell B. (4) 8.2 Write down the: 8.2.1 Half-reaction for half-cell B. (2) 8.2.2 Cell notation for this cell. (3) 8.2.3 TWO standard conditions for this cell. (2) 8.2.4 Energy conversion that takes place when this cell is in operation. (1) The concentration of the Ag+ is increased in half-cell A. 8.4 What effect will an increase in the concentration of the Ag+ in half-cell A have on the initial emf of the cell? Choose from INCREASES, DECREASES, or REMAINS THE SAME. (1) [13] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 16 September 2024 Preparatory Examination NSC QUESTION 9 (Start on a new page.) The diagram below shows a simplified electrolytic cell used to electroplate an iron bar with copper. power source M N Concentrated CuCℓ2(aq) 9.1 Define the term electrolyte. (2) The graph below, NOT drawn to scale, represents the changes in the mass of electrode M during the electroplating process. 9.2 Which electrode M or N represents the iron bar? Write down a half-reaction to support your answer. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 17 September 2024 Preparatory Examination NSC 9.3 It is observed that the concentration of the electrolyte remains constant during the electrolytic process. Write down the name or formula of electrode N. Explain the answer. (3) 9.4 Calculate the value X as shown on the graph if a constant current of 1,5 A passes through the cell. (5) The copper used in this electrolytic cell is NOT PURE. It contains a small percentage of zinc. 9.5 It is observed that iron bar is not coated with zinc. Explain this observation in terms of the relative oxidising strengths of the substances. (2) [15] TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences/P2 1 September 2024 Preparatory Examination NSC 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 NAME/NAAM SYMBOL/SIMBOOL VALUE/WAARDE Standard pressure p 1,013 x 105 Pa Standaarddruk Molar gas volume at STP Vm 22,4 dm3∙mol-1 Molêre gasvolume by STD Standard temperature Standaardtemperatuur T 273 K Charge on electron e -1,6 x 10-19 C Lading op elektron Avogadro's constant NA 6,02 x 1023 mol-1 Avogadro-konstante TABLE 2: FORMULAE/TABEL 2: FORMULES m N n= n= M NA n m V c= or/of c= n= V MV Vm c a v a na = pH = -log[H3O+] c b v b nb Kw = [H3O+][OH-] = 1 x 10-14 at/by 298 K Eθcell = Eθcathode − Eθanode / E θsel = Ekatode θ − E θanode or/of Eθcell = Ereduction θ − Eθoxidation / E θsel = Ereduksie θ − E θoksidasie or/of Eθcell = Eθoxidising agent − Ereducing θ agent / E sel = E oksideermi ddel − Ereduseermi ddel θ θ θ Q Q where n is the number of electrons/ I= n= waar n die aantal elektrone is t e Copyright reserved

Downloaded from hlayiso.com Physical Sciences/P2 2 September 2024 Preparatory Examination NSC 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) (III) (IV) (V) (VI) (VII) (VIII) Atomic number 1 KEY/SLEUTEL Atoomgetal 2 2,1 H He 1 29 4 3 4 Electronegativity Symbol 5 6 7 8 9 10 1,0 1,5 1,9 Cu 2,0 2,5 3,0 3,5 4,0 Li Be Elektronegatiwiteit 63,5 Simbool B C N O F Ne 7 9 11 12 14 16 19 20 11 12 13 14 15 16 17 18 0,9 Na 1,2 Mg Approximate relative atomic mass 1,5 Aℓ 1,8 Si 2,1 P 2,5 S 3,0 Cℓ Ar 23 24 Benaderde relatiewe atoommassa 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 0,8 K 1,0 Ca 1,3 Sc 1,5 Ti 1,6 V 1,6 Cr 1,5 Mn 1,8 Fe 1,8 Co 1,8 Ni 1,9 Cu 1,6 Zn 1,6 Ga 1,8 Ge 2,0 As 2,4 Se 2,8 Br Kr 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 0,8 Rb 1,0 Sr 1,2 Y 1,4 Zr Nb 1,8 Mo 1,9 Tc 2,2 Ru 2,2 Rh 2,2 Pd 1,9 Ag 1,7 Cd 1,7 In 1,8 Sn 1,9 Sb 2,1 Te 2,5 I Xe 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 0,7 Cs 0,9 Ba La 1,6 Hf Ta W Re Os Ir Pt Au Hg 1,8 Tℓ 1,8 Pb 1,9 Bi 2,0 Po 2,5 At Rn 133 137 139 179 181 184 186 190 192 195 197 201 204 207 209 87 88 89 0,7 Fr 0,9 Ra Ac 58 59 60 61 62 63 64 65 66 67 68 69 70 71 226 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

Downloaded from hlayiso.com Physical Sciences/P2 3 September 2024 Preparatory Examination NSC TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD-REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E θ (V) F2(g) + 2e− ⇌ 2F− + 2,87 Co 3+ +e − ⇌ Co2+ + 1,81 H2O2 + 2H+ +2e− ⇌ 2H2O +1,77 − MnO 4 + 8H+ + 5e− ⇌ Mn2+ + 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 + − ⇌ Mn 2+ + 2H2O + 1,23 Pt2+ + 2e− ⇌ Pt + 1,20 Br2(ℓ) + 2e− ⇌ 2Br− + 1,07 − NO 3 + + 4H + 3e − ⇌ NO(g) + 2H2O + 0,96 Increasing reducing ability/Toenemende reduserende vermoë Hg2+ + 2e − ⇌ Hg(ℓ) + 0,85 Ag+ + e− ⇌ Increasing oxidising ability/Toenemende oksiderende vermoë Ag + 0,80 − NO 3 + 2H+ + e− ⇌ NO2(g) + H2O + 0,80 Fe3+ + e− ⇌ Fe2+ + 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 Cu2+ + 2e− ⇌ Cu + 0,34 2− SO 4 + 4H+ + 2e− ⇌ SO2(g) + 2H2O + 0,17 Cu2+ + e− ⇌ Cu + + 0,16 Sn4+ + 2e− ⇌ Sn 2+ + 0,15 S + 2H+ + 2e− ⇌ H2S(g) + 0,14 + 2H + 2e − ⇌ H2(g) 0,00 Fe3+ + 3e− ⇌ Fe − 0,06 Pb2+ + 2e− ⇌ Pb − 0,13 Sn2+ + 2e− ⇌ Sn − 0,14 Ni2+ + 2e− ⇌ Ni − 0,27 Co2+ + 2e− ⇌ Co − 0,28 Cd2+ + 2e− ⇌ Cd − 0,40 Cr 3+ +e − ⇌ Cr 2+ − 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 Mn2+ + 2e− ⇌ Mn − 1,18 Aℓ3+ + 3e− ⇌ Aℓ − 1,66 Mg2+ + 2e− ⇌ Mg − 2,36 Na + e + − ⇌ Na − 2,71 Ca2+ + 2e− ⇌ Ca − 2,87 2+ Sr + 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

Downloaded from hlayiso.com Physical Sciences/P2 4 September 2024 Preparatory Examination NSC TABLE 4B: STANDARD REDUCTION POTENTIALS TABEL 4B: STANDAARD-REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E θ (V) Li+ + e− ⇌ Li − 3,05 K+ + e− ⇌ K − 2,93 + Cs + e − ⇌ Cs − 2,92 Ba2+ + 2e− ⇌ Ba − 2,90 2+ Sr + 2e − ⇌ Sr − 2,89 Ca2+ + 2e− ⇌ Ca − 2,87 Na+ + e− ⇌ Na − 2,71 Mg 2+ + 2e − ⇌ Mg − 2,36 Aℓ3+ + 3e− ⇌ Aℓ − 1,66 Mn 2+ + 2e − ⇌ Mn − 1,18 Cr2+ + 2e− ⇌ Cr − 0,91 Increasing oxidising ability/Toenemende oksiderende vermoë 2H2O + 2e − ⇌ H2(g) + 2OH − − 0,83 Zn2+ + 2e− ⇌ Zn − 0,76 Increasing reducing ability/Toenemende reduserende vermoë 3+ Cr + 3e − ⇌ Cr − 0,74 Fe2+ + 2e− ⇌ Fe − 0,44 Cr3+ + e− ⇌ Cr2+ − 0,41 2+ Cd + 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 Sn4+ + 2e− ⇌ Sn2+ + 0,15 Cu 2+ − +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 Fe 3+ − +e ⇌ Fe 2+ + 0,77 − NO 3 + 2H + e + − ⇌ NO2(g) + H2O + 0,80 Ag + e + − ⇌ Ag + 0,80 Hg2+ + 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 + − ⇌ 2+ Mn + 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 − ⇌ Mn 2+ + 4H2O + 1,51 H2O2 + 2H +2 e + − ⇌ 2H2O +1,77 Co + e3+ − ⇌ Co2+ + 1,81 F2(g) + 2e− ⇌ 2F− + 2,87 Copyright reserved