Physical Sciences Grade 12 P2 2026 QP (Eng)

Prediction hlayiso mock exams Practice Series: Grade 12 NSC Preparation WWW.HLAYISO.COM NATIONAL SENIOR CERTIFICATE GRADE 12 PHYSICAL SCIENCES: CHEMISTRY (P2) PREDICTION EXAMINATION 2026 MARKS: 150 TIME: 3 hours This question paper consists of 14 pages and 4 data sheets. Copyright reserved Please turn over

Physical Sciences/P2 2 Hlayiso/Prediction 2026 NSC Prediction INSTRUCTIONS AND INFORMATION 1. Write your centre number and examination number 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 subquestions, e.g. between QUESTION 2.1 and QUESTION 2.2. 6. You may use a non-programmable calculator. 7. Show ALL formulae and substitutions in ALL calculations. 8. Round off your FINAL numerical answers to a minimum of TWO decimal places. 9. Give brief motivations, discussions, etc. where required. 10. You are advised to use the attached DATA SHEETS. 11. Write neatly and legibly. Copyright reserved Please turn over

Physical Sciences/P2 3 Hlayiso/Prediction 2026 NSC Prediction QUESTION 1: MULTIPLE-CHOICE QUESTIONS Various 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 numbers (1.1 to 1.10) in the ANSWER BOOK, e.g. 1.11 E. 1.1 Decane, C10 H22 , is cracked according to the balanced equation below. C10 H22 → 2C2 H4 + X Which ONE of the following CORRECTLY describes compound X? MOLECULAR SATURATED OR FORMULA UNSATURATED A C6 H12 Unsaturated (2) B C8 H18 Saturated C C6 H14 Saturated D C6 H14 Unsaturated 1.2 Which ONE of the following compounds contains a CARBONYL group but does NOT contain a HYDROXYL group? A Propanone B Propanoic acid C Propan-2-ol D Propan-1-ol (2) 1.3 Which ONE of the following alkenes will form 2-chloro-2-methylbutane as the MAJOR product when it reacts with hydrogen chloride, HCℓ(g)? A Pent-1-ene B Pent-2-ene C But-1-ene D 2-methylbut-2-ene (2) Copyright reserved Please turn over

Physical Sciences/P2 4 Hlayiso/Prediction 2026 NSC Prediction 1.4 The potential energy diagram for a reaction is shown below. Potential energy (kJ·mol–1 ) 120 products 70 reactants 40 Course of reaction Which ONE of the following is CORRECT for the REVERSE reaction? HEAT OF REACTION, ∆H ACTIVATION ENERGY (kJ·mol–1 ) (kJ·mol–1 ) A +30 80 (2) B –30 50 C –30 80 D +30 50 1.5 A catalyst increases the rate of a chemical reaction because it … A increases the average kinetic energy of the reactant particles. B provides an alternative reaction pathway of lower activation energy. C increases the heat of reaction. D increases the concentration of the reactants. (2) 1.6 The reaction below is at equilibrium in a closed container. N2 (g) + 3H2 (g) ⇌ 2NH3 (g) ∆H < 0 The volume of the container is now DECREASED at constant temperature. Which ONE of the following combinations is CORRECT when the new equilibrium is established? AMOUNT OF NH3 (g) VALUE OF Kc A Increases Increases B Decreases Remains the same (2) C Remains the same Decreases D Increases Remains the same Copyright reserved Please turn over

Physical Sciences/P2 5 Hlayiso/Prediction 2026 NSC Prediction 1.7 Consider the reaction below. HCO–3 (aq) + H2 O(ℓ) ⇌ H2 CO3 (aq) + OH– (aq) Which ONE of the following is a CONJUGATE ACID-BASE PAIR in this reaction? A HCO–3 and OH– B H2 O and H2 CO3 C H2 CO3 and HCO–3 D H2 O and HCO–3 (2) 1.8 The pH of a solution is 3 at 25 ◦ C. Which ONE of the following statements about this solution is CORRECT? A [OH– ] = 1 × 10–11 mol·dm–3 B [H3 O+ ] = 3 mol·dm–3 C [H3 O+ ] < [OH– ] D [OH– ] = 1 × 10–3 mol·dm–3 (2) 1.9 Which ONE of the following ions will OXIDISE iron, Fe(s), to Fe2+ (aq), but will NOT oxidise copper, Cu(s), under standard conditions? A Ag+ (aq) B Pb2+ (aq) C Zn2+ (aq) D Mg2+ (aq) (2) 1.10 Impure copper, containing silver as an impurity, is refined in an electrolytic cell with a copper(II) sulphate solution as electrolyte. Which ONE of the following statements is CORRECT for this cell? A The impure copper is connected to the negative terminal of the power source. B The mass of the pure copper electrode decreases. C Cu2+ (aq) ions are reduced at the cathode. D The silver is oxidised and Ag+ (aq) ions go into the solution. (2) [20] Copyright reserved Please turn over

Physical Sciences/P2 6 Hlayiso/Prediction 2026 NSC Prediction QUESTION 2 (Start on a new page.) The letters A to F in the table below represent six organic compounds. H H H H H H H Br H H H A H C C C C C C H B H C C C C C C H H H H H H H H H C C H C C H H H H H H H H H H C CH3 CH(OH)CH(CH3 )CH3 D CH3 (CH2 )3 COOH E CH3 COCH(CH3 )CH3 F Pentanal 2.1 Write down the LETTER(S) that represent(s) EACH of the following: 2.1.1 An unsaturated hydrocarbon (1) 2.1.2 A SECONDARY alcohol (1) 2.1.3 TWO compounds that are FUNCTIONAL isomers of each other (1) 2.2 Write down the IUPAC name of: 2.2.1 Compound A (3) 2.2.2 Compound B (3) 2.2.3 Compound C (2) 2.3 Write down the STRUCTURAL FORMULA of ONE POSITIONAL isomer of compound C. (2) 2.4 Compound D reacts with an alcohol X in the presence of concentrated sulphuric acid to form an organic compound Y and water. Analysis of compound Y gives the following results: • Percentage carbon by mass: 64,62 % • Percentage hydrogen by mass: 10,77 % • The rest of the compound is oxygen. • Molar mass of Y: 130 g·mol–1 2.4.1 Write down the type of reaction that takes place. (1) 2.4.2 Determine the MOLECULAR FORMULA of compound Y by means of a calculation. (4) 2.4.3 Write down the STRUCTURAL FORMULA of compound Y. (2) [20] Copyright reserved Please turn over

Physical Sciences/P2 7 Hlayiso/Prediction 2026 NSC Prediction QUESTION 3 (Start on a new page.) Learners compare the vapour pressures of four organic compounds, A to D, at 25 ◦ C. The results are shown in the table below. COMPOUND IUPAC NAME MOLAR MASS VAPOUR (g·mol–1 ) PRESSURE (kPa) A Methyl ethanoate 74 28,8 B 2-methylpropan-1-ol 74 1,4 C Butan-1-ol 74 0,9 D Propanoic acid 74 0,5 3.1 Define the term vapour pressure. (2) 3.2 Give a reason why this is a FAIR comparison. (1) 3.3 Which compound (A, B, C or D) has the HIGHEST boiling point? Give a reason for the answer by referring to the data in the table. (2) 3.4 Compounds A and D are functional isomers. Fully explain the difference in the vapour pressures of compounds A and D by referring to the TYPES of intermolecular forces. (4) 3.5 Compounds B and C are compared. 3.5.1 Write down the type of structural isomers that B and C represent. Choose from CHAIN, POSITIONAL or FUNCTIONAL. (1) 3.5.2 Explain why the vapour pressure of compound B is HIGHER than that of compound C. (3) [13] Copyright reserved Please turn over

Physical Sciences/P2 8 Hlayiso/Prediction 2026 NSC Prediction QUESTION 4 (Start on a new page.) The flow diagram below shows how hexan-2-ol can be used to prepare other organic compounds. P, Q and R represent organic compounds and I to V represent different reactions. Reaction I Compound P Hexan-2-ol (major product) conc. H2 SO4 , heat at he Reaction IV n III rong ti o st eac nol, Reaction II R tha e Br2 Reaction V HBr O H, .K nc co Compound R Compound Q 4.1 Write down the type of reaction (ADDITION, ELIMINATION or SUBSTITUTION) represented by: 4.1.1 Reaction II (1) 4.1.2 Reaction V (1) 4.2 For Reaction I, write down the: 4.2.1 IUPAC name of compound P (2) 4.2.2 STRUCTURAL FORMULA of the MINOR organic product (2) 4.3 Is compound R a PRIMARY, SECONDARY or TERTIARY haloalkane? Give a reason for the answer. (2) 4.4 Using STRUCTURAL FORMULAE for the organic compounds, write down a balanced equation for Reaction III. (5) 4.5 For Reaction IV, write down the: 4.5.1 NAME or FORMULA of the inorganic reactant (1) 4.5.2 Reaction condition, besides the reactant in QUESTION 4.5.1 (1) 4.6 Write down the IUPAC name of compound Q. (2) [17] Copyright reserved Please turn over

Physical Sciences/P2 9 Hlayiso/Prediction 2026 NSC Prediction QUESTION 5 (Start on a new page.) Learners use the reaction of magnesium, Mg(s), with EXCESS dilute sulphuric acid, H2 SO4 (aq), to investigate factors that affect reaction rate. The balanced equation for the reaction is: Mg(s) + H2 SO4 (aq) → MgSO4 (aq) + H2 (g) In each experiment 0,36 g of magnesium is added to 100 cm3 of the acid. The conditions are summarised in the table below. EXPERIMENT STATE OF CONCENTRATION OF TEMPERATURE DIVISION OF Mg H2 SO4 (mol·dm–3 ) (◦ C) 1 Ribbon 0,5 25 2 Ribbon 1,0 25 3 Powder 0,5 25 4 Ribbon 0,5 35 5.1 Define the term reaction rate. (2) 5.2 For the comparison of experiments 1 and 2, write down the: 5.2.1 Independent variable (1) 5.2.2 ONE controlled variable (1) The hydrogen gas produced in experiment 1 is collected in a gas syringe. The graph below (NOT drawn to scale) shows the total volume of H2 (g) collected against time. At t = 60 s, 260 cm3 of H2 (g) has been collected. Volume of H2 (g) (cm3 ) X 260 0 60 Time (s) 5.3.1 Give a reason why the gradient of the graph DECREASES as the reaction proceeds. (1) 5.3.2 Calculate the average rate (in mol·s–1 ) at which H2 SO4 (aq) is used up during the first 60 s. Take the molar gas volume at 25 ◦ C as 24 dm3 ·mol–1 . (4) 5.3.3 Calculate the final volume of H2 (g), X, shown on the graph. (3) Copyright reserved Please turn over

Physical Sciences/P2 10 Hlayiso/Prediction 2026 NSC Prediction 5.4 How will the final volume of H2 (g) collected in experiment 3 compare to that in experiment 1? Choose from GREATER THAN, LESS THAN or EQUAL TO. (1) 5.5 Use the collision theory to explain why the initial reaction rate in experiment 3 is HIGHER than that in experiment 1. (3) The Maxwell-Boltzmann distribution curves, P and Q, for experiments 1 and 4 are shown below. Ea is the activation energy. Number of particles P Q Ea Kinetic energy 5.6 Which curve, P or Q, represents experiment 4? Give a reason for the answer. (2) [18] Copyright reserved Please turn over

Physical Sciences/P2 11 Hlayiso/Prediction 2026 NSC Prediction QUESTION 6 (Start on a new page.) Phosphorus pentachloride, PCℓ5 (g), decomposes in a closed container according to the balanced equation: PCℓ5 (g) ⇌ PCℓ3 (g) + Cℓ2 (g) ∆H > 0 6.1 State Le Chatelier’s principle. (2) 6.2 An unknown mass of PCℓ5 (g) is sealed in an empty 2 dm3 container and heated to 250 ◦ C. When equilibrium is reached, 8,52 g of Cℓ2 (g) is present in the container. The equilibrium constant, Kc , for the reaction at 250 ◦ C is 0,04. Calculate the INITIAL mass of PCℓ5 (g) that was sealed in the container. (8) The equilibrium mixture is now disturbed at times t1 , t2 and t3 . The graph below (NOT drawn to scale) shows how the rates of the forward and reverse reactions change with time. The volume of the container is kept constant. Reaction rate Forward reaction Reverse reaction t1 t2 t3 Time 6.3 Write down the change that was made to the equilibrium mixture at: 6.3.1 t1 (1) 6.3.2 t2 (1) 6.4 At t3 the temperature of the system is changed. 6.4.1 Was the temperature INCREASED or DECREASED? (1) 6.4.2 Fully explain the answer to QUESTION 6.4.1 by using Le Chatelier’s principle. (3) 6.4.3 How will the value of Kc after t3 compare with its value before t3 ? Choose from GREATER THAN, LESS THAN or EQUAL TO. (1) 6.5 In a separate experiment, the volume of the container is DECREASED at constant temperature. How will the number of moles of PCℓ5 (g) at the new equilibrium compare with that at the original equilibrium? Choose from INCREASES, DECREASES or REMAINS THE SAME. Give a reason for the answer. (2) [19] Copyright reserved Please turn over

Physical Sciences/P2 12 Hlayiso/Prediction 2026 NSC Prediction QUESTION 7 (Start on a new page.) 7.1 The table below shows the ionisation constants, Ka , of two acids at 25 ◦ C. ACID FORMULA Ka AT 25 ◦ C Hydrofluoric acid HF 6,8 × 10–4 Hypochlorous acid HOCℓ 3,0 × 10–8 7.1.1 Define a weak acid. (2) 7.1.2 Solutions of HF and HOCℓ of EQUAL concentration are compared. Which solution has the HIGHER pH? Give a reason for the answer by referring to the data in the table. (2) Household bleach contains sodium hypochlorite, NaOCℓ, dissolved in water. 7.1.3 Will a solution of NaOCℓ be ACIDIC, BASIC or NEUTRAL? (1) 7.1.4 Write down a balanced equation to explain the answer to QUESTION 7.1.3. (3) 7.2 A standard solution of oxalic acid, (COOH)2 , of concentration 0,10 mol·dm–3 is used to determine the concentration of a sodium hydroxide solution, NaOH(aq). The balanced equation for the reaction is: (COOH)2 (aq) + 2NaOH(aq) → (COONa)2 (aq) + 2H2 O(ℓ) In the titration, 25 cm3 of the oxalic acid solution is exactly neutralised by 20 cm3 of the NaOH(aq). 7.2.1 Which ONE of the following indicators is the most suitable for this titration? Choose from METHYL ORANGE, BROMOTHYMOL BLUE or PHENOLPHTHALEIN. Give a reason for the answer. (2) 7.2.2 Calculate the concentration of the NaOH(aq). (4) In another experiment, 15 cm3 of the same NaOH(aq) is added to 10 cm3 of the same oxalic acid solution. Assume that the volumes are additive and that the temperature is 25 ◦ C. 7.2.3 Calculate the pH of the resulting solution. (6) [20] Copyright reserved Please turn over

Physical Sciences/P2 13 Hlayiso/Prediction 2026 NSC Prediction QUESTION 8 (Start on a new page.) A galvanic cell is set up using a silver half-cell, Ag(s) | Ag+ (aq), and a half-cell of an unknown metal M in a solution containing M2+ (aq) ions, as shown below. The cell operates under standard conditions. V salt bridge M Ag M2+ (aq) Ag+ (aq) The initial reading on the voltmeter is 1,24 V. After the cell has operated for a while, the mass of the silver electrode has INCREASED. 8.1 State the standard conditions under which this cell operates. (2) 8.2 Which electrode, M or Ag, is the CATHODE? Give a reason for the answer. (2) 8.3 Identify metal M by means of a calculation. (5) 8.4 Write down the balanced net (overall) cell reaction that takes place in this cell. (3) [12] Copyright reserved Please turn over

Physical Sciences/P2 14 Hlayiso/Prediction 2026 NSC Prediction QUESTION 9 (Start on a new page.) A concentrated copper(II) bromide solution, CuBr2 (aq), is electrolysed using two carbon electrodes, A and B, as shown in the simplified diagram below. +– A B CuBr2 (aq) 9.1 Define the term electrolysis. (2) 9.2 Write down the half-reaction that takes place at electrode A. (2) 9.3 Bromine, and NOT oxygen, is formed at electrode A. Explain this observation by referring to the relative strengths of the REDUCING AGENTS present. (3) 9.4 During the electrolysis the mass of electrode B increases by 1,27 g. Calculate the number of electrons that flowed through the external circuit. (4) [11] TOTAL: 150 Copyright reserved

Physical Sciences/P2 1 Hlayiso/Prediction 2026 NSC Prediction DATA FOR PHYSICAL SCIENCES GRADE 12 PAPER 2 (CHEMISTRY) TABLE 1: PHYSICAL CONSTANTS NAME SYMBOL VALUE Standard pressure pθ 1,013× 105 Pa Molar gas volume at STP Vm 22,4 dm3 ·mol–1 Standard temperature Tθ 273 K Charge on electron e 1,6× 10–19 C Avogadro’s constant NA 6,02× 1023 mol–1 TABLE 2: FORMULAE m N n= n= M NA n m V c= or c = n= V MV Vm ca Va na = pH = – log[H3 O+ ] cb Vb nb Kw = [H3 O+ ][OH– ] = 1 × 10–14 at 298 K Eθcell = Eθcathode – Eθanode or Ecell = Ereduction – Eθoxidation θ θ or Ecell = Eoxidising agent – Eθreducing agent θ θ Copyright reserved

Physical Sciences/P2 2 Hlayiso/Prediction 2026 NSC Prediction TABLE 3: THE PERIODIC TABLE OF ELEMENTS 1 2 13 14 15 16 17 18 (I) (II) 3 4 5 6 7 8 9 10 11 12 (III) (IV) (V) (VI) (VII) (VIII) 1 2 Atomic number 2,1 H He 1 KEY 4 29 3 4 5 6 7 8 9 10 1,0 1,5 Electronegativity 1,9 Cu Symbol 2,0 2,5 3,0 3,5 4,0 Li Be B C N O F Ne 7 9 63,5 11 12 14 16 19 20 11 12 13 14 15 16 17 18 0,9 Na 1,2 Mg 1,5 Aℓ 1,8 Si 2,1 P 2,5 S 3,0 Cℓ Ar Approximate relative atomic mass 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 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 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 Copyright reserved

Physical Sciences/P2 3 Hlayiso/Prediction 2026 NSC Prediction TABLE 4A: STANDARD REDUCTION POTENTIALS Half-reactions Eθ (V) F2 (g) + 2e– ⇌ 2F– + 2,87 Co3+ + e– ⇌ Co2+ + 1,81 H2 O2 + 2H+ + 2e– ⇌ 2H2 O + 1,77 MnO–4 + 8H+ + 5e– ⇌ Mn2+ + 4H2 O + 1,51 Cℓ2 (g) + 2e– ⇌ 2Cℓ– + 1,36 Cr2 O2– + – 3+ 7 + 14H + 6e ⇌ 2Cr + 7H2 O + 1,33 + – O2 (g) + 4H + 4e ⇌ 2H2 O + 1,23 MnO2 + 4H+ + 2e– ⇌ Mn2+ + 2H2 O + 1,23 Pt2+ + 2e– ⇌ Pt + 1,20 Br2 (ℓ) + 2e– ⇌ 2Br– + 1,07 NO–3 + 4H+ + 3e– ⇌ NO(g) + 2H2 O + 0,96 Hg2+ + 2e– ⇌ Hg(ℓ) + 0,85 Ag+ + e– ⇌ Ag + 0,80 NO3 + 2H+ + e– ⇌ NO2 (g) + H2 O – + 0,80 Fe3+ + e– ⇌ Fe2+ + 0,77 O2 (g) + 2H+ + 2e– ⇌ H2 O2 + 0,68 Increasing strength of oxidising agents I2 + 2e– ⇌ 2I– Increasing strength of reducing agents + 0,54 Cu+ + e– ⇌ Cu + 0,52 SO2 + 4H+ + 4e– ⇌ S + 2H2 O + 0,45 2H2 O + O2 + 4e– ⇌ 4OH– + 0,40 Cu2+ + 2e– ⇌ Cu + 0,34 SO4 + 4H+ + 2e– ⇌ SO2 (g) + 2H2 O 2– + 0,17 Cu2+ + e– ⇌ Cu+ + 0,16 Sn4+ + 2e– ⇌ Sn2+ + 0,15 S + 2H+ + 2e– ⇌ H2 S(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 Fe2+ + 2e– ⇌ Fe – 0,44 Cr3+ + 3e– ⇌ Cr – 0,74 Zn2+ + 2e– ⇌ Zn – 0,76 2H2 O + 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 Copyright reserved

Physical Sciences/P2 4 Hlayiso/Prediction 2026 NSC Prediction TABLE 4B: STANDARD REDUCTION POTENTIALS Half-reactions 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 2H2 O + 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 Increasing strength of oxidising agents Cd2+ + 2e– ⇌ Cd Increasing strength of reducing agents – 0,40 Co2+ + 2e– ⇌ Co – 0,28 Ni2+ + 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– ⇌ H2 S(g) + 0,14 Sn4+ + 2e– ⇌ Sn2+ + 0,15 Cu2+ + e– ⇌ Cu+ + 0,16 SO4 + 4H+ + 2e– ⇌ SO2 (g) + 2H2 O 2– + 0,17 Cu2+ + 2e– ⇌ Cu + 0,34 2H2 O + O2 + 4e– ⇌ 4OH– + 0,40 SO2 + 4H+ + 4e– ⇌ S + 2H2 O + 0,45 Cu+ + e– ⇌ Cu + 0,52 I2 + 2e– ⇌ 2I– + 0,54 O2 (g) + 2H+ + 2e– ⇌ H2 O2 + 0,68 Fe3+ + e– ⇌ Fe2+ + 0,77 NO–3 + 2H+ + e– ⇌ NO2 (g) + H2 O + 0,80 Ag+ + e– ⇌ Ag + 0,80 Hg2+ + 2e– ⇌ Hg(ℓ) + 0,85 NO–3 + 4H+ + 3e– ⇌ NO(g) + 2H2 O + 0,96 Br2 (ℓ) + 2e– ⇌ 2Br– + 1,07 Pt2+ + 2e– ⇌ Pt + 1,20 MnO2 + 4H+ + 2e– ⇌ Mn2+ + 2H2 O + 1,23 O2 (g) + 4H+ + 4e– ⇌ 2H2 O + 1,23 Cr2 O2– + – 3+ 7 + 14H + 6e ⇌ 2Cr + 7H2 O + 1,33 Cℓ2 (g) + 2e ⇌ 2Cℓ– – + 1,36 MnO–4 + 8H+ + 5e– ⇌ Mn2+ + 4H2 O + 1,51 H2 O2 + 2H+ + 2e– ⇌ 2H2 O + 1,77 Co3+ + e– ⇌ Co2+ + 1,81 F2 (g) + 2e– ⇌ 2F– + 2,87 Copyright reserved