Physical Sciences Grade 12 P2 Gauteng Mock 2023 QP (Eng)

PREPARATORY EXAMINATION 2023 10842 PHYSICAL SCIENCES: CHEMISTRY (PAPER 2) TIME: 3 hours MARKS: 150 19 pages + 4 data sheets P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 2 (PAPER 2) 10842/23 INSTRUCTIONS AND INFORMATION 1. Write your name in the appropriate space on the ANSWER BOOK. 2. This question paper consists of NINE questions. Answer ALL the questions in the ANSWER BOOK. 3. Start EACH question (e.g. QUESTION 2 and QUESTION 3) on a NEW page. 4. Number the answers correctly according to the numbering system used in this question paper. 5. Leave ONE line open between subquestions, e.g. between QUESTION 2.1 and QUESTION 2.2. 6. You may use a non-programmable calculator. 7. You may use appropriate mathematical instruments. 8. You are advised to use the attached DATA SHEETS. 9. Show ALL formulae and substitutions in ALL calculations. 10. Round-off your FINAL numerical answers to a minimum of TWO decimal places. 11. Give brief motivations, discussions, et cetera where required. 12 Write neatly and legibly. P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 3 (PAPER 2) 10842/23 QUESTION 1: MULTIPLE-CHOICE QUESTIONS Four options are given 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 numbers (1.1 to 1.10) in the ANSWER BOOK, e.g. 1.11 E. 1.1 The EMPIRICAL formula of hexanoic acid is: A C3H6O2 B C6H6O2 C C6H12O2 D C3H6O (2) 1.2 Which intermolecular forces are present between molecules of C7H15CHO? A Only dipole-dipole forces B Dipole-dipole forces, dispersion (London) forces and hydrogen bonding forces C Dispersion (London) forces and hydrogen bonding forces D Dipole-dipole forces and dispersion (London) forces (2) P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 4 (PAPER 2) 10842/23 1.3 The structures of four organic compounds are shown below. COMPOUND 1 COMPOUND 2 COMPOUND 3 COMPOUND 4 Which of these compounds will decolourise bromine water FAST? A 1 and 2 B 2 and 3 C 3 and 4 D 1 and 4 (2) 1.4 Which of the following statements best explains the role of a catalyst? A It lowers the activated complex. B It increases the concentration of the reactants and therefore increases the rate of the reaction. C It provides an alternative path with lower activation energy for the reaction. D It increases the net activation energy. (2) P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 5 (PAPER 2) 10842/23 1.5 The energy distribution curves for a fixed mass of gas at two different temperatures, T1 and T2, are shown below: Number of particles Energy Which ONE of the following is the correct interpretation of the curves for the change in temperature from T1 to T2? Activation energy Number of effective collisions A Stays the same Increased B Decreased Decreased C Decreased Increased D Stays the same Decreased (2) 1.6 Each of the reactions represented below is at equilibrium in a closed container. In which of these reactions will an INCREASE IN PRESSURE (by decreasing the volume) favour the formation of products? A N2O4(g) ⇌ 2NO2(g) B PCℓ5(g) ⇌ PCℓ3(g) + Cℓ2(g) C N2(g) + 3H2(g) ⇌ 2NH3(g) D NO2(g) + CO(g) ⇌ NO(g) + CO2(g) (2) P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 6 (PAPER 2) 10842/23 1.7 Consider beakers A and B as illustrated below. 200 cm3 of 150 cm3 of 0,25 mol∙dm-3 0,1 mol∙dm-3 NaOH (aq) NaOH (aq) Beaker A Beaker B 20 cm3 of the NaOH(aq) solution in beaker A is added to the NaOH(aq) solution in beaker B. Which of the following represents the correct calculation for the new concentration of Na+(aq) ions in beaker B? A 0,015 + 0,005 0,17 B 0,015 + 0,05 0,17 C 0,015 x 0,005 0,15 D 0,015 + 0,005 0,15 (2) 1.8 When a galvanic (voltaic) cell delivers current, the purpose of the salt bridge is to … A allow electrons to move in the cell. B ensure electrical neutrality in the cell. C prevent the two solutions from mixing. D allow electrons to travel from the cathode to the anode. (2) P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 7 (PAPER 2) 10842/23 1.9 Which of the following metals is the strongest reducing agent? A Ag B Zn C Cu D Aℓ (2) 1.10 Gaseous chlorine (Cℓ2), used to disinfect the water in public swimming pools, reacts with water according to the following balanced equation: Cℓ2 + H2O ⇌ HOCℓ + HCℓ The addition of chlorine changes the pH of water in swimming pools. Which of the following substances must be added to public swimming pools periodically to increase the pH? A NH4Cℓ B Na2CO3 C KCℓ D H2SO4 (2) [20] P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 8 (PAPER 2) 10842/23 QUESTION 2 (Start on a new page.) A to F in the table below represent six organic compounds. A B Pentan-3-one C D Methyl butanoate E F CH3(CH2)3CH3 2.1 Consider the organic compound A. 2.1.1 Is it a PRIMARY, SECONDARY or TERTIARY alcohol? Give a reason for the answer. (2) 2.1.2 Write down the IUPAC name for the above-mentioned compound. (2) 2.1.3 The above-mentioned compound undergoes an elimination reaction. Write down the STRUCTURAL FORMULA of the major product that is formed. (2) 2.2 Consider the organic compound B. 2.2.1 Define the term functional isomer. (2) Write down the: 2.2.2 Homologous series to which the above-mentioned compound belongs (1) 2.2.3 IUPAC name of its functional isomer (2) 2.2.4 Letter that represents its positional isomer (1) 2.3 Write down the balanced equation using MOLECULAR FORMULAE for the complete combustion of compound F. (3) [15] P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 9 (PAPER 2) 10842/23 QUESTION 3 (Start on a new page.) Three structural isomers with molecular formula C6H14 are used to investigate the effect of branching on the physical properties of hydrocarbons. HYDROCARBON STRUCTURAL FORMULAE A B C The results obtained for the first TWO investigations are shown in the table below. INVESTIGATION 1 INVESTIGATION 2 HYDROCARBON MELTING POINT BOILING POINT (°C) (°C) A -154 60 B -129 58 C -100 50 3.1 Define the term melting point. (2) 3.2 Write down the independent variable for INVESTIGATION 1. (1) 3.3 Explain why these three organic compounds are called structural isomers. (2) 3.4 Write down the type of intermolecular forces present between molecules of (1) these isomers. 3.5 Explain the difference in melting points between molecules A and B. (4) P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 10 (PAPER 2) 10842/23 For INVESTIGATION 3, the vapour pressure (in mmHg) measured at 25 °C, is shown in the table below: VAPOUR PRESSURE (mmHg) 235 319 211 3.6 Using the information of INVESTIGATION 2 and INVESTIGATION 3, match the correct vapour pressure with the appropriate molecule (A – C). Write down the letters (A – C) below each other with the corresponding vapour pressure next to each letter. (2) 3.7 Fully explain the answer in QUESTION 3.6. (3) [15] P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 11 (PAPER 2) 10842/23 QUESTION 4 (Start on a new page.) The flow diagram below shows how ethene can be used to prepare various organic compounds. The letters A to F represent different organic reactions. CH3(CH2)3COOH A Ethene B CH3CH2OH Compound X E F C D Bromoethane 4.1 Identify the type of reaction represented by: 4.1.1 B (1) 4.1.2 D (1) 4.2 Write down TWO reaction conditions for reaction B. (2) 4.3 For reaction A, write down the: 4.3.1 NAME of the inorganic reactant (1) 4.3.2 CHEMICAL FORMULA of the catalyst needed (1) 4.4 For reaction C: 4.4.1 Use STRUCTURAL FORMULAE and write down a balanced chemical equation. (3) 4.4.2 Explain why no water should be present during this reaction. (1) P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 12 (PAPER 2) 10842/23 4.5 Reaction E represents the conversion of the alcohol into organic compound X. Write down the: 4.5.1 Type of reaction (1) 4.5.2 CHEMICAL FORMULA of the catalyst needed (1) 4.5.3 STRUCTURAL FORMULA of compound X (2) 4.5.4 IUPAC name of compound X (2) 4.6 Reaction F takes place in the presence of warm, concentrated NaOH. Use CONDENSED STRUCTURAL FORMULAE and write down a balanced equation for the reaction. (3) 4.7 Large straight-chained alkanes can be catalytically cracked to produce shorter-chained alkenes and branched alkanes which are more suitable for use in petrol. The reaction below indicates the catalytic cracking of octane. CH3(CH2)6CH3 → CH2=CH2 + Compound Y 4.7.1 Write down the IUPAC name of compound Y. (1) 4.7.2 Briefly explain why shorter-chained alkenes and branched alkanes are more suitable for use in petrol than large straight-chained alkanes. (2) [22] P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 13 (PAPER 2) 10842/23 QUESTION 5 (Start on a new page.) The following apparatus was used by a group of learners in an investigation to find out how surface area affects the rate of reaction between excess solid magnesium ribbon and dilute nitric acid with a concentration of 0,05 mol∙dm-3. During the reaction, the gas formed is collected in the measuring cylinder. The balanced equation for the reaction is: Mg(s) + 2HNO3(aq) → Mg(NO3)2(aq) + H2(g) The summary of their investigation is tabulated below. EXPERIMENT MASS OF MAGNESIUM (g) STATE OF DIVISION I 2 Ribbon cut into 5 small pieces II 2 Ribbon as one large piece The results for experiment I are plotted on the graph below. Volume of gas produced (cm3) Time (s) P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 14 (PAPER 2) 10842/23 5.1 Besides the mass and the volume of the reactants, give ONE other variable that must be kept constant during this investigation. (1) 5.2 Write down the dependent variable in this investigation. (1) 5.3 Use the graph to calculate the average rate of the reaction (in cm3∙s-1) between 2 and 2,5 minutes. (3) 5.4 Will the rate of the reaction at 250 s be GREATER THAN, LESS THAN or EQUAL TO the rate calculated in QUESTION 5.3? Give a reason for the answer. (2) 5.5 Predict how the gradient of the graph for experiment II will compare to that of experiment I. Write down only INCREASE, DECREASE or STAY THE SAME. (1) 5.6 Calculate the mass of magnesium metal that remains in the conical flask when the reaction has stopped. Assume that the molar volume is 24 dm3∙mol-1 at room temperature. (5) 5.7 Medication used to relieve headaches is available as powders or tablets. Use the collision theory to explain why powders provide faster relief than tablets. (2) [15] P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 15 (PAPER 2) 10842/23 QUESTION 6 (Start on a new page.) Hydrogen gas is prepared by the reaction of methane and steam, as shown in the following balanced chemical equation: CH4(g) + H2O(g) ⇌ CO(g) + 3H2(g) ΔH = +206 kJ The methane (CH4) and steam (H2O) are sealed in a 2 dm3 container to react and are allowed to reach equilibrium at temperature T. 6.1 State Le Chatelier’s Principle. (2) 6.2 Use Le Chatelier's principle to explain how the following changes will affect the yield of H2(g): 6.2.1 Adding more CH4 (3) 6.2.2 A decrease in the volume of the container (3) The sketch graph below shows the changes in the number of moles of methane, steam and carbon monoxide as the reaction proceeds for the preparation of H2 gas in a 2 dm3 container. 6.3 Write down a reason why there is no change in the number of moles of each of the gases between times t1 and t2. (1) 6.4 Use the information on the graph and calculate the equilibrium constant, Kc, for this reaction at temperature T. (7) 6.5 The temperature T is decreased. How will this change affect the Kc-value for the above reaction? Write only INCREASE, DECREASE or REMAIN THE SAME. (1) [17] P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 16 (PAPER 2) 10842/23 QUESTION 7 (Start on a new page.) The balanced equations below represent the ionisation of sulphuric acid in water: - Step 1: H2SO4(ℓ) + H2O(ℓ) ⇌ H3O+(aq) + HSO4 (aq) - Step 2: HSO4 (aq) + H2O(ℓ) ⇌ H3O+(aq) + SO4-2(aq) 7.1 Is H2SO4 a STRONG or WEAK acid? Give a reason for the answer. (2) 7.2 Write down the FORMULAE of the conjugated acid-base pairs in step 2. (2) 7.3 H2SO4 is diprotic. Write down the meaning of the term diprotic. (2) 7.4 Write down the FORMULA of the ampholyte in the above reaction. (1) 7.5 An impure sample of potassium hydroxide pellets with a mass of 11,2 g is added to 0,09 mole of sulphuric acid with a volume of 600 cm3. It reacts according to the balanced chemical equation given below: H2SO4(aq) + 2KOH(s)  K2SO4(aq) + 2H2O(ℓ) 7.5.1 Calculate the initial pH of the sulphuric acid used in this reaction. (5) 7.5.2 The percentage purity of the potassium hydroxide pellets used is 80%. Calculate the number of moles of pure potassium hydroxide that react with H2SO4. (4) 7.5.3 Determine which reactant is in excess and hence state whether the final solution is ACIDIC, BASIC or NEUTRAL. (3) [19] P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 17 (PAPER 2) 10842/23 QUESTION 8 (Start on a new page.) A galvanic cell is set up using a manganese rod, Mn, and an unknown metal X. The initial EMF measured under standard conditions is 1,05 V. The electrons flow from manganese to metal X in the external circuit. 8.1 Is the reaction that occurs in this cell spontaneous? Write down only YES or NO. Give a reason for the answer. (2) 8.2 Which electrode, X or Mn, is the anode? (1) 8.3 Use calculations to identify metal X. (5) 8.4 For this cell, write down the: 8.4.1 TWO standard conditions (2) 8.4.2 Cell notation (2) 8.4.3 Reduction half reaction (2) [14] P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 18 (PAPER 2) 10842/23 QUESTION 9 (Start on a new page.) The diagram below represents the purification of copper ore to pure copper. The cell also contains zinc, silver and platinum impurities. CuSO4(aq) impurities The graph shows the initial relationship between the mass of Cu deposited versus the time. Mass of Cu deposited (g) Time(s) P.T.O.

PHYSICAL SCIENCES: CHEMISTRY 19 (PAPER 2) 10842/23 9.1 Write down the energy conversion that takes place in this cell. (1) 9.2 At which electrode, A or B, would pure copper be deposited? (1) 9.3 Write down the half-reaction that takes place at the anode. (2) 9.4 How will the gradient of the graph be affected as the reaction is allowed to proceed until completion? Write only INCREASE, DECREASE or REMAIN THE SAME. (1) 9.5 Refer to the relative strengths of reducing agents to explain why zinc (Zn) will NOT be deposited at the cathode. (3) 9.6 When the current flows for 30 minutes, 15 g of pure copper was deposited at one of the electrodes. 9.6.1 Calculate the number of moles of copper deposited. (3) 9.6.2 Determine the number of moles of electrons that flows through the circuit while 15 g of copper is deposited. (2) [13] TOTAL: 150 END

PHYSICAL SCIENCES: CHEMISTRY 20 (PAPER 2) 10842/23 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 T 273 K Standaardtemperatuur Charge on electron e -1,6 x 10-19 C Lading op elektron Avogadro’s’ number NA 6,02×1023 Avogadro se nommer TABLE 2: FORMULAE/TABEL 2: FORMULES m N n n M NA n m V c or c  n V MV Vm c a Va n  a pH = -log[H3O+] cb Vb nb Eθcell  Eθcathode  Eθanode / Eθsel  Ekatode θ  Eθanode Eθcell  Ereduction θ  Eθoxidation / Eθsel  Ereduksie θ  Eθoksidasie E θcell  E θoxidising agent  E θreducing agent / E θsel  E θoksideermi ddel  E reduseermi θ ddel

PHYSICAL SCIENCES: CHEMISTRY 21 (PAPER 2) 10842/23 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/ KEY/SLEUTEL Atoomgetal 1 2 2,1 H He 1 29 4 Electro negativity/ Symbol/ 3 4 1,9 Cu 5 6 7 8 9 10 Li Be Elektronegatiwiteit Simbool B C N O F Ne 1,0 1,5 63,5 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 Approximate relative atomic mass/ Aℓ Si P S Cℓ Ar 0,9 1,2 1,5 1,8 2,1 2,5 3,0 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 Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tℓ Pb Bi Po At Rn 0,7 0,9 1,6 1,8 1,8 1,9 2,0 2,5 133 137 139 179 181 184 186 190 192 195 197 201 204 207 209 87 88 89 0,7 Fr 0,9 Ra Ac 226 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

PHYSICAL SCIENCES: CHEMISTRY 22 (PAPER 2) 10842/23 TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E (V) F2(g) + 2e ⇌ 2F + 2,87 3+ Co + e  ⇌ Co2+ + 1,81 H2O2 + 2H+ +2e ⇌ 2H2O +1,77  MnO 4 + 8H+ + 5e ⇌ 2+ Mn + 4H2O + 1,51 Cℓ2(g) + 2e ⇌ 2Cℓ + 1,36 2 Cr2O 7 + 14H+ + ⇌ 2Cr3+ + 7H2O + 1,33 6e 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 3 + 4H+ + 3e ⇌ NO(g) + 2H2O + 0,96 ⇌ Increasing reducing ability/Toenemende reduserende vermoë Hg2+ + 2e Hg(ℓ) + 0,85 Ag+ + e ⇌ Ag + 0,80 NO 3 + 2H+ + e ⇌ Increasing oxidising ability/Toenemende oksiderende vermoë 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 2+ Cu + 2e  ⇌ Cu + 0,34 2 SO 4 + 4H+ + 2e ⇌ SO2(g) + 2H2O + 0,17 Cu2+ + e ⇌ Cu+ + 0,16 4+ Sn + 2e  ⇌ Sn2+ + 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 Cr3+ + e ⇌ Cr2+  0,41 2+ Fe + 2e  ⇌ Fe  0,44 Cr3+ + 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 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

PHYSICAL SCIENCES: CHEMISTRY 23 (PAPER 2) 10842/23 TABLE 4B: STANDARD REDUCTION POTENTIALS TABEL 4B: STANDAARD REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E (V) Li+ + e ⇌ Li  3,05 K + + e ⇌ K  2,93 Cs+ + e ⇌ Cs  2,92 2+ Ba + 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 oxidising ability/Toenemende oksiderende vermoë Increasing reducing ability/Toenemende reduserende vermoë 2H2O + 2e H2(g) + 2OH  0,83 Zn2+ + 2e ⇌ Zn  0,76 Cr3+ + 3e ⇌ Cr  0,74 Fe2+ + 2e ⇌ Fe  0,44 Cr3+ + e ⇌ Cr2+  0,41 Cd2+ + 2e ⇌ Cd  0,40 Co2+ + 2e ⇌ Co  0,28 2+ Ni + 2e  ⇌ Ni  0,27 Sn2+ + 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 2+ Cu + 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 3+ Co + e  ⇌ Co2+ + 1,81 F2(g) + 2e ⇌ 2F + 2,87