Physical Sciences Grade 12 P2 Northern Cape November 2019 QP

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 1 ————————————————————— DEPARTMENT OF EDUCATION ————————————————————— DEPARTEMENT VAN ONDERWYS ————————————————————— LEFAPHA LA THUTO ————————————————————— ISEBE LEZEMFUNDO ————————————————————— PROVINCIAL PREPARATORY EXAMINATION GRADE 12 PHYSICAL SCIENCES P2: CHEMISTRY SEPTEMBER 2019 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/Grade 12 2 September 2019 INTRUCTIONS AND INFORMATION 1. This question paper consists of TEN questions. Answer ALL the questions in the ANSWER BOOK. 2. Start EACH question on a NEW page in the ANSWER BOOK. 3. Number the answers correctly according to the numbering system used in this question paper. 4. Leave ONE line between two sub questions, for example between QUESTION 2.1 and QUESTION 2.2. 5. You may use a non-programmable calculator. 6. You may use appropriate mathematical instruments. 7. You are advised to use the attached DATA SHEETS. 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, etc. where required. 11. Write neatly and legibly. Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 3 September 2019 QUESTION 1: MULTIPLE-CHOICE QUESTIONS Various possible options are provided as 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 example 1.11 E. 1.1 The group of atoms which determine the chemical properties of carboxylic acids is called the ... A formyl group. B carbonyl group. C carboxyl group. D hydroxyl group. (2) 1.2 Consider the condensed structural formula of an organic compound below. CH3 CH3 CH CH CH2 C C CH3 CH3 The IUPAC name of this compound is … A 2,3-dimethylhept-5-yne. B 5,6-dimethylhept-2-yne. C 2,3-methylhept-2-yne. D 5,6-dimethylhept-3-yne. (2) 1.3 Which ONE of the following compounds, of comparable molecular mass, has the highest vapour pressure? A Pentane B Butan-2-one C Propanoic acid D Ethyl methanoate (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 4 September 2019 1.4 The heat of reaction (∆H) and the activation energy (Ea) for a reaction are −111 kJ·mol-1 and 43 kJ·mol-1 respectively. The activation energy for the reverse reaction will be ... A -43 kJ·mol-1 B 111 kJ·mol-1 C 154 kJ·mol-1 D 68 kJ·mol-1 (2) 1.5 The Maxwell-Boltzmann energy distribution curves (A, B, C and D) below show the number of particles versus kinetic energy for a reaction at four different temperatures. The minimum kinetic energy needed for effective collisions to take place is represented by E. Which ONE of the curves (A, B, C or D) represents the reaction that will take place the fastest? (2) Number of particulars A B C D E Kinetic energy 1.6 The expression for the equilibrium constant (KC) of a hypothetical reaction is given as follows: [D]2 [C] KC = [A]3 Which ONE of the following equations represents this reaction? A 3A(s) ⇌ C(g) + 2D(g) B 3A(ℓ) ⇌ C(aq) + 2D(aq) C 3A(aq) + B(s) ⇌ C(g) + D2(g) D 3A(aq) + B(s) ⇌ C(aq) + 2D(aq) (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 5 September 2019 1.7 Which ONE of the following indicators is most suitable for the titration of ethanoic acid with sodium hydroxide? Indicator pH A 0,2 - 1,8 B 2,9 - 4,0 C 6,0 - 7,6 D 11,6 - 14,0 (2) 1.8 The electrode where oxidation occurs in all electrochemical cells is the ... A anode. B cathode. C positive electrode. D negative electrode. (2) 1.9 During the electrolysis of a concentrated sodium chloride solution, the hydrogen gas is formed as a result of ... A reduction of hydrogen ions. B oxidation of hydrogen ions. C reduction of water. D oxidation of water. (2) 1.10 Which ONE of the following nutrients is primarily responsible for the growth of leaves in a plant? A Carbon B Nitrogen C Potassium D Phosphorous (2) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 6 September 2019 QUESTION 2 (Start on a new page.) The letters A to H in the table below are used to represent eight organic compounds. H O H A Propanoic acid B H C C C H H H H H O C D But-2-ene H C C O C H H H E 1,2-dichloro-3-methylbutane F CH3CH2COOCH2CH3 H H H C C G CH3CCCH(C2H5)CH2CH3 H H n 2.1 Write down the letter(s) that represent(s): 2.1.1 An alkyl halide (1) 2.1.2 Two compounds that are functional isomers (1) 2.2 Write down the IUPAC name of: 2.2.1 Compound B (2) 2.2.2 Compound F (2) 2.2.3 The organic acid used in the preparation of compound C (1) 2.3 Write down the structural formula of compound G. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 7 September 2019 2.4 Compound H is a polymer. For this polymer write down: 2.4.1 The structural formula of the monomer used in its preparation (1) 2.4.2 The type of polymerisation reaction taking place during its preparation (1) 2.5 1 mole of CnH2n burns completely in 192 g oxygen according to the following UNBALANCED equation: CnH2n + O2 → CO2 + H2O Balance the given equation and determine the molecular formula of C nH2n with the aid of a calculation. (5) [17] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 8 September 2019 QUESTION 3 (Start on a new page.) The graph below shows the results obtained when investigating the relationship between boiling points of straight chain alkanes and alcohols and the number of carbon atoms per molecule. Graph of boiling point versus number of carbon atoms 400 350 Boiling Point (K) 300 250 Alkane 200 150 Alcohol 100 50 1 2 3 4 Number of carbon atoms 3.1 What trend in boiling point is observed for the alkanes? (2) 3.2 Both butane and butan-1-ol contain four carbon atoms per molecule. 3.2.1 How does the boiling point of butan-1-ol compare to that of butane as shown in the graph? Write down only HIGHER THAN, LOWER THAN or EQUAL TO. (1) 3.2.2 Write down the names of TWO intermolecular forces which exist between butan-1-ol molecules. (2) 3.2.3 By refering to the different types of intermolecular forces, briefly explain the difference in boiling points of butane and butan-1-ol. (3) [8] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 9 September 2019 QUESTION 4 (Start on a new page.) Study the flow diagram below, which represents various organic reactions, and answer the questions that follow. Hydration Reaction 1 Alcohol Y CH3CHCH2 ++ H2 Z = Reaction 5 Reaction 2 Reaction 3 Reaction 4 X 2-chloropropane 4.1 Reaction 1 is an example of an addition reaction. For Reaction 1 write down: 4.1.1 The type of addition reaction (1) 4.1.2 The NAME or FORMULA of a suitable catalyst (1) 4.2 Write down the structural formula and IUPAC name of compound Y. (3) 4.3 Is alcohol Y a PRIMARY, SECONDARY or TERTIARY alcohol? Give a reason for your answer. (2) 4.4 Reaction 5 is an elimination reaction. For Reaction 5 write down: 4.4.1 ONE reaction condition required (1) 4.4.2 The IUPAC name of compound X (1) 4.5 Using STRUCTURAL FORMULAE for the organic compounds involved, write down a balanced equation for Reaction 4. (5) 4.6 Both Reactions 3 and 4 take place in the presence of an inorganic reagent. 4.6.1 Name the type of reaction represented by Reaction 3. (1) 4.6.2 Write down the TWO reaction conditions which would favour Reaction 3 instead of Reaction 4. (2) [17] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 10 September 2019 QUESTION 5 (Start on a new page.) The reaction between sodium carbonate (Na2CO3) and sulphuric acid (H2SO4) was used to investigate one of the factors affecting reaction rate. The balanced equation is given below. Na2CO3(s) + H2SO4(aq) → Na2SO4(aq) + CO2(g) + H2O(ℓ) Two experiment are conducted as illustrated below. EXPERIMENT 1 EXPERIMENT 2 Na2CO3 lumps H2SO4 Na2CO3 powder 150,00 150,00 g Mass balance g In both experiments the same amount of sodium carbonate is added to an excess of sulphuric acid solution in a conical flask placed on a mass balance. The mass of the flask together with its contents is recorded every 15 s. 5.1 Define the term reaction rate. (2) 5.2 For the investigation described above, write down: 5.2.1 The independent variable (1) 5.2.2 ONE controlled variable (1) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 11 September 2019 The results obtained in EXPERIMENT 1 are shown in the table below. Time (s) 0 15 30 45 60 75 90 105 120 Mass (g) 150,00 147,50 146,60 146,00 145,80 145,70 145,60 145,60 145,60 5.3 Write down the NAME or FORMULA of the substance responsible for the decrease in mass. (1) 5.4 How long does it take for the reaction in EXPERIMENT 1 to be completed? (1) 5.5 How will the rate of the reaction in EXPERIMENT 2 compare to that in EXPERIMENT 1? Write down GREATER THAN, SMALLER THAN or EQUAL TO. Briefly explain your answer by referring to the collision theory. (3) 5.6 The sketch graph below (not drawn to scale) represents the results obtained for EXPERIMENT 1. 150,00 mass/g 145,60 time/s 5.6.1 Use the information in the graph to determine the mass of sodium carbonate that has reacted in EXPERIMENT 1. (5) 5.6.2 Redraw the above sketch graph in your ANSWER BOOK. On the same set of axes, sketch the curve obtained for EXPERIMENT 2. Label your graph as Exp.2. (2) [16] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 12 September 2019 QUESTION 6 (Start on a new page.) The following balanced equation represents the production of methanol (CH3OH) using carbon monoxide gas (CO) and hydrogen gas (H2). CO(g) + 2H2(g) ⇌ CH3OH(g) ∆H = +128,49 kJ∙mol-1 The reaction reaches equilibrium at 380 K. 6.1 Define the term dynamic equilibrium. (2) 6.2 An unknown mass of carbon monoxide gas (CO) is injected into a 2 dm3 closed vessel, containing 1,5 moles of hydrogen gas (H2). Upon reaching equilibrium at 380 K, 0,75 moles of hydrogen gas (H2) remains in the vessel. If the equilibrium constant, (Kc), for this reaction is 6,27 at 380 K, calculate the initial mass of carbon monoxide gas (CO) injected into the vessel. (9) 6.3 For the given equilibrium reaction, write down the K c value for the reverse reaction at 380 K. (2) 6.4 The same amounts of CO(g) and H2(g) as before are now heated in a LARGER VESSEL and the reaction reaches equilibrium at 380 K. How will each of the following be affected by this change? Write down INCREASES, DECREASES or REMAINS THE SAME. Explain your answer. 6.4.1 The Kc value (2) 6.4.2 The equilibruim yield of methanol (CH3OH) (2) 6.5 The temperature is now decreased to 300 K and a new equilibrium is established. How will the amount of methanol (CH3OH) formed at 300 K compare to that formed at 380 K? Write down INCREASES, DECREASES or REMAINS THE SAME. Explain your answer using Le Chatelier's principle. (3) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 13 September 2019 QUESTION 7 (Start on a new page.) 7.1 Define an acid according to the BrØnsted-Lowry theory. (2) 7.2 Calculate the pH of a sodium hydroxide solution of concentration 0,75 mol·dm-3. (5) 7.3 Seashells contain calcium carbonate (CaCO3). In a test to find the percentage of calcium carbonate (CaCO3) present in seashells, 75 cm3 of a 0,5 mol·dm-3 hydrochloric acid (HCℓ) solution is added to a 5 g sample of seashells.The acid is in excess. The balanced equation for the reaction is given below. CaCO3(s) + 2HCℓ(aq) → CaCℓ2(aq) + CO2(g) + H2O(ℓ) The excess acid required 22 cm3 of the above sodium hydroxide solution for complete neutralisation according to the following balanced equation: HCℓ(aq) + NaOH(aq) → NaCℓ(aq) + H2O(ℓ) Calculate the percentage of calcium carbonate (CaCO3) in the sample of seashells. (8) [15] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 14 September 2019 QUESTION 8 (Start on a new page.) A galvanic cell is set up using a magnesium half-cell and an iodine half-cell as shown in the diagram below. 8.1 Write down the name of the component labelled X. (1) 8.2 Name the standard reference electrode against which all other electrode potentials are measured. (1) 8.3 The I2 | I- half-cell requires platinum when the galvanic cell is operating. What is the function of the platinum? (1) 8.4 Write down the cell notation for the above cell. (3) 8.5 The voltmeter is now replaced with a 3 V bulb. Will the bulb glow to its maximum brightness? Support your answer with a suitable calculation. (5) 8.6 The cell reactions in the above galvanic cell reaches equilibrium. How will this affect the glowing of the above bulb? Give a reason for your answer. (2) [13] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 15 September 2019 QUESTION 9 (Start on a new page.) Aluminium is extracted by electrolysis as illustrated in the simplified diagram below. Negative carbon cathode Positivecarbon Positive carbonanodes anodes Molten cryolite + Aluminium oxide Aluminium outlet Steel container 9.1 Write down the energy conversion that takes place in the above cell. (1) 9.2 Write down an equation for the half-reaction that occurs at the anode. (2) 9.3 Give a reason why the anodes must be replaced frequently. (2) 9.4 Before the extraction process, aluminium oxide is heated with cryolite. Give a reason why cryolite is added to the aluminium oxide. (1) 9.5 Write down TWO negative impacts of the extraction of aluminium on the environment. (2) [8] Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 16 September 2019 QUESTION 10 (Start on a new page.) The following flow diagram illustrates some of the processes in the manufacture of fertilisers. H2SO4 H2 FERTILIZER Y PROCESS A NH3 NO + H2O X O2 AIR BROWN GAS LIQUID Z 10.1 Identify the following in the flow diagram: 10.1.1 Name of substance X (1) 10.1.2 Process A (1) 10.1.3 Fertilizer Y (1) 10.1.4 The brown gas (1) 10.2 Write down the balanced equation for the formation of liquid Z. (3) Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 17 September 2019 10.3 A farmer wishes to buy a fertilizer which will ensure a good maize harvest. He chooses a 50 kg bag of fertiliser with the following numbers written on the label: 7:2:1(X). 10.3.1 Determine the value of X, if the bag contains 1,2 kg of potassium. (4) 10.3.2 Will this fertilizer lead to a good crop yield? Briefly explain your answer. (3) 10.4 The excessive use of fertilizers can lead to eutrophication. Write down TWO possible ways farmers can reduce eutrophication. (2) [16] GRAND TOTAL: 150 Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 1 September 2019 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 Standaarddruk p 1,013 x 105 Pa 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 E θcell  Ereduction θ  E θoxidation / E θsel  Ereduksie θ  E θoksidasie or/of Eθcell  Eθoxidisingagent  Ereducing θ agent / E sel  Eoksideermiddel  Ereduseermiddel θ θ θ Copyright reserved Please turn over

Physical Sciences P2/Grade 12 Downloaded from hlayiso.com 2 September 2019 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 Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 3 September 2019 TABLE 4A: STANDARD REDUCTION POTENTIALS TABEL 4A: STANDAARD-REDUKSIEPOTENSIALE Half-reactions/Halfreaksies E θ (V) F2(g) + 2e ⇌ 2F + 2,87 Co3+ + 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 ⇌ Mn2+ + 2H2O + 1,23  Pt 2+ + 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 Increasing oxidising ability/Toenemende oksiderende vermoë 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 ⇌ 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 Fe2+ + 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 Copyright reserved Please turn over

Downloaded from hlayiso.com Physical Sciences P2/Grade 12 4 September 2019 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 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  ⇌  1,18 Increasing oxidising ability/Toenemende oksiderende vermoë 2+ Mn Mn + 2e Cr2+ + 2e ⇌ Cr  0,91 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 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 ⇌ H2S(g) + 0,14 Sn4+ + 2e ⇌ Sn2+ + 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 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 ⇌ 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 ⇌ Mn2+ + 4H2O + 1,51 H2O2 + 2H+ +2 e ⇌ 2H2O +1,77 Co3+ + e ⇌ Co2+ + 1,81 F2(g) + 2e ⇌ 2F + 2,87 Copyright reserved Please turn over