# Technical Sciences Grade 12 P2 Eastern Cape Mock 2018 QP

> Grade 12 Technical Sciences Paper 2 question paper from the Eastern Cape Mock Exam 2018 (English), 21 pages. Read online or download the free PDF.

- Page: https://www.hlayiso.com/library/tech-science-p2-gr12-qp-eng-sept2018/73893ebf-6d24-4de4-8764-bd9d620a7a03
- Updated: 2026-09-27
- Subject: Technical Sciences
- Grade: Grade 12
- Document type: Question paper
- Year: 2018
- Exam period: Eastern Cape Mock Exam
- Paper: 2
- Curriculum: CAPS
- Pages: 21

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Technical Sciences · Grade 12 · Eastern Cape Mock Exam · 2018. Question paper, 21 pages. Read online or download the PDF.

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(EC/SEPTEMBER 2018)                                          TECHNICAL SCIENCES
P2                                                           1

                                     NATIONAL
                                SENIOR CERTIFICATE

                                       GRADE 12

                                  SEPTEMBER 2018

                         TECHNICAL SCIENCES P2

 MARKS:      150
 TIME:       3 hours

                      This question paper consists of 17 pages, including 4 data sheets.

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2                                TECHNICAL SCIENCES P2                 (EC/SEPTEMBER 2018)

    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 ANSWERBOOK.

 3.    Start EACH question on a NEW page in the ANSWER BOOK.

 4.    Number your 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.    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.

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(EC/SEPTEMBER 2018)                      TECHNICAL 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 number
 (1.1–1.10) in the ANSWER BOOK, for eg. 1.11 E.

 1.1    Study the structural formula of an organic compound below.

                                           H     Br

                                     H      C    C    H

                                           H     H

        The homologous series to which the compound belongs is …

        A     alkanes.

        B     ketones.

        C     aldehydes.

        D     haloalkanes.                                                                (2)

 1.2    Consider the reaction:

                           CH3Br + KOH            CH3OH    +     KBr

        The type of reaction taking place is …

        A     addition.

        B     hydration.

        C     substitution.

        D     combustion.                                                                 (2)

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4                                                         TECHNICAL SCIENCES P2                 (EC/SEPTEMBER 2018)

 1.3                           Study the vapour pressure versus temperature graphs for a secondary and a
                               tertiary alcohol. Both compounds have the molecular formula C4H10O. The
                               atmospheric pressure is 100 kPa.

                                        GRAPH OF VAPOUR PRESSURE VERSUS TEMPERATURE

       VAPOUR PRESSURE (kPa)
                               120

                                   80

                                   40

                                                 20             60            100         120
                                                               TEMPERATURE (oC)

                               Which ONE of the following is the boiling point of the TERTIARY alcohol?

                               A        80 oC

                               B        70 oC

                               C        100 oC

                               D        110 oC                                                                  (2)

 1.4                           In a redox reaction a reducing agent always:

                               A        Loses electrons

                               B        Gains electrons

                               C        Undergoes reduction

                               D        Undergoes a decrease in oxidation number                                (2)

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(EC/SEPTEMBER 2018)                     TECHNICAL SCIENCES P2                             5

 1.5 A Technical science learner wants to store copper (II) sulphate solution
     CuS04in a metal container. The container must not develop a leak due to a
     chemical reaction between the metal and the solution.

                      Metal container
                                                       Copper (II) sulphate solution

       Which ONE of the following metals must the learner use as the container?

       A     Aℓ

       B     Ni

       C     Ag

       D     Sn                                                                           (2)

 1.6 Which ONE of the following CORRECTLY describes the energy change in an
     electrolytic cell?

       A     Electrical energy changes to chemical energy.

       B     Electrical energy changes to mechanical energy.

       C     Chemical energy changes to electrical energy.

       D     Chemical energy to mechanical energy.                                        (2)

 1.7 The image of a candle is found to be 5 cm behind a flat mirror.

       The distance between the candle and the mirror is …

       A     0 cm.

       B     5 cm.

       C     longer than 5 cm.

       D     shorter than 5 cm.                                                           (2)

 1.8 The bending of light as it moves from one medium to another called:

       A     Dispersion

       B     Diffraction

       C     Refraction

       D     Reflection                                                                   (2)

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6                                TECHNICAL SCIENCES P2                    (EC/SEPTEMBER 2018)

 1.9    Consider the section of the electromagnetic spectrum below.

        Which ONE of the electromagnetic radiations shown in the diagram above
        has the longest wavelength?

        A     Infrared

        B     Ultraviolet

        C     Microwave

        D     Visible light                                                                    (2)

 1.10   A ray of light passes from glass to air as shown in the diagram below.

                                  35o

        The critical angle for glass is 38o.

        The light ray will undergo the following:

        A     Reflection

        B     Total internal reflection

        C     Refraction towards the normal

        D     Refraction away from the normal                                                  (2)
                                                                                              [20]

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(EC/SEPTEMBER 2018)                       TECHNICAL SCIENCES P2                                    7

 QUESTION 2 (Start on a NEW page.)

 The letters A to F represent six organic compounds.

 A     HC          C   CH2        CH3          B                 Polythene
                                                                      O
 C          2-chloro-2-methylpropane           D
                                                   CH3CH2        O    C    CH2CH3
                                                                               H
               H       O      H
                                                                     CH3   O
 E     H       C       C      C     H          F
                                                   CH3CHCH           CH    C     H
               H              H
                                                       CH2CH3              H

 2.1 Write down the LETTER that represents the following:

       2.1.1       A hydrocarbon                                                                  (1)

       2.1.2       A ketone                                                                       (1)

       2.1.3       A compound with the general formula CnH2n-2                                    (1)

 2.2 Write down the NAME of the homologous series to which EACH of the
     following belong:

       2.2.1       Compound A                                                                     (1)

       2.2.2       Compound D                                                                     (1)

       2.2.3       Compound F                                                                     (1)

 2.3 Write down the structural formula of compound C.                                             (2)

 2.4 Write down the IUPAC name of each of the following:

       2.4.1       Compound E                                                                     (2)

       2.4.2       Compound F                                                                     (3)

 2.5 Write down the condensed structural formula of a positional isomer of
     compound A.                                                                                  (2)

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8                               TECHNICAL SCIENCES P2                 (EC/SEPTEMBER 2018)

 2.6 Compound D is prepared from a carboxylic acid and an alcohol in the
     presence of concentrated sulphuric acid.

       Write down the:

       2.6.1    Structural formula of the carboxylic acid used                          (2)

       2.6.2    IUPAC name of compound D                                                (2)

 2.7 Compound B is a macromolecule from which synthetic materials derived from
     organic compounds are produced.

       2.7.1    Define the term macromolecule.                                          (2)

       2.7.2    Write down single term for the underlined phrase.                       (1)

       2.7.3    Write down the structural formula of polythene.                        (2)
                                                                                      [24]

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(EC/SEPTEMBER 2018)                     TECHNICAL SCIENCES P2                             9

 QUESTION 3 (Start on a NEW page)

 During an investigation to compare the viscosity of alkanes, learners used a
 stopwatch to measure the time it takes a FIXED volume of each alkane to flow from
 a pipette as shown below.

 The learners’ results are recorded in the table below.

 COMPOUND                     ALKANE                TIME OF FLOW (minutes)
    A                  2,2 – dimethylpropane                 0,214
    B                     2 – methylbutane                   0,297
    C                         pentane                        0,350

 3.1    Define the term viscosity.                                                       (2)

 3.2    Which alkane (A, B or C) has the HIGHEST viscosity?                              (1)

 3.3    Explain fully the answer to QUESTION 3.2.                                        (3)

 3.4    Which alkane (A, B or C) has the HIGHEST vapour pressure?                        (1)

 3.5    Compounds A and B have LOWER boiling points than compound C.

        Write down a definition of boiling point.                                        (2)

 3.6    Compound C is a component of petrol.

        Write down a balanced equation for the reaction of compound C with excess        (3)
        oxygen.
                                                                                        [12]

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10                             TECHNICAL SCIENCES P2                      (EC/SEPTEMBER 2018)

 QUESTION 4

 The flow diagram given below shows how prop-1-ene can be converted to other
 organic compounds.

       propane        Reaction 1     Pprop-1-ene      HYDRATION        Compound Y

                              Reaction 2    HBr

                                                        Reaction 3
                                   Compound X

                                  (Major Product)
                                Product)
 4.1 Is propane a SATURATED or UNSATURATED compound?                                      (1)

 4.2 Write down the TYPE of ADDITION reaction represented by:

       4.2.1    Reaction 1                                                                (1)

       4.2.2    Reaction 2                                                                (1)

 4.3 For Reaction 1 write down the:

       4.3.1    Name of the catalyst used                                                 (1)

       4.3.2    Name or Formula of the inorganic reagent used                             (1)

 4.4 For Reaction 3 write down:

       4.4.1    ONE reaction condition                                                    (1)

       4.4.2    Balanced equation using structural formulae for organic reagents         (6)
                                                                                        [12]

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(EC/SEPTEMBER 2018)                      TECHNICAL SCIENCES P2                                   11

 QUESTION 5 (Start on a NEW page)

 5.1 Consider the reaction represented by the balanced equation.

                      SnCℓ4(aq) +   Br (aq)               SnCℓ2(aq)   + Br2(ℓ)

       5.1.1    Define oxidation in terms of electron transfer.                                  (2)

       5.1.2    Write down the oxidation number of the underlined substance in the
                equation.                                                                        (1)

       5.1.3    Determine by calculation whether the reaction is spontaneous.                    (5)

 5.2 The following reactions occur spontaneously in galvanic cells P, Q, R and S.

            CELL                              NET CELL REACTION

               P                        Ni    + Au3+              Ni2+ + Au

               Q                        Mn    + Ni2+              Mn2+ + Ni

               R                        Aℓ    + Mn2+              Aℓ3+ + Mn

               S                         Aℓ    +   Au3+           Au + Aℓ3+

       Which cell (P, Q, R or S) will produce the HIGHEST EMF?

       Explain the answer without performing any calculation.                                    (3)

 5.3 Another galvanic cell, T, is constructed using Ni/ Ni2+ and Aℓ/ Al3+ half-cells.

       For cell T.

       5.3.1    Which electrode is the anode (Ni or Aℓ)?                                         (1)

       5.3.2    Write down the balanced overall ionic equation for the reaction that
                takes place.                                                                     (3)

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12                              TECHNICAL SCIENCES P2                      (EC/SEPTEMBER 2018)

 5.4 The diagram given below shows a galvanic cell constructed under standard
     conditions.

                                          V

                                           X

                Cu                                                Zn

               Cu2+                                                Zn2+

       Write down the:

       5.4.1    Energy change taking place when the cell is in operation                   (2)

       5.4.2    TWO standard conditions for this cell                                      (2)

       5.4.3    TWO functions of component X                                               (2)

       5.4.4    Cell notation                                                              (3)

 5.5 Fuel cells and biodiesel can be used as alternative energy sources to petrol or
     petroleum diesel.

       Write down ONE:

       5.5.1    Advantage of using biodiesel in place of petrol                            (1)

       5.5.2    Disadvantage of using biodiesel in cars                                   (1)
                                                                                         [26]

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(EC/SEPTEMBER 2018)                        TECHNICAL SCIENCES P2                              13

 QUESTION 6 (Start on a NEW page)

 Consider the electrochemical cell used for the electrolysis of copper (II) chloride
 solution below.

 Graphite rods are used as electrodes.

                                        Power
                                        Source

                      A                                       B
                                                           CuCℓ2(aq)

 6.1    Define the term electrolysis.                                                         (2)

 6.2    Is the power source AC or DC?                                                         (1)

 6.3    In which direction will Cu2+ ions move in the solution?

        Write down only TOWARDS A or TOWARDS B.                                               (1)

 6.4    Give a reason why copper (II) chloride crystals must be dissolved into the
        solution before electrolysis.                                                         (2)

 6.5    Write down:

        6.5.1    ONE observable change at electrode A                                         (1)

        6.5.2    The NAME or FORMULA of the oxidising agent                                   (1)

 6.6    Write down the half reaction taking place at electrode B.                             (2)
                                                                                             [10]

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14                             TECHNICAL SCIENCES P2                    (EC/SEPTEMBER 2018)

 QUESTION 7 (Start on a NEW page)

 The diagrams given below (A and B) show TWO phenomena that can take place
 when a ray of light strikes a glass prism.

 Study the ray diagrams and answer the questions that follow.

 DIAGRAM A

                                                       ά            X

 DIAGRAM B

                                                                Z
                                                 θ

                                Y

 7.1 Define the term reflection.                                                           (2)

 7.2 Write down the NAME of:

       7.2.1     Ray X                                                                     (1)

       7.2.2     Ray R                                                                     (1)

       7.2.3     Ray Y                                                                     (1)

       7.2.4     Angle labelled θ in diagram B                                             (1)

       7.2.5     The phenomenon taking place inside the prism in diagram A                 (1)

       7.2.6     The phenomenon shown in diagram B                                         (1)

 7.3 State TWO requirements for the phenomenon taking place inside the prism in
     diagram A.                                                                            (2)

 7.4 Is ray Z refracted AWAY or TOWARDS the normal as it travels inside the prism?

       Give a reason.                                                                      (3)

 7.5 How does the angle θ in diagram B compare in size to the angle ά in diagram
     A?

       Write only LARGER THAN, SMALLER THAN or EQUAL TO.

       Explain the answer.                                                                 (3)
                                                                                          [16]

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(EC/SEPTEMBER 2018)                     TECHNICAL SCIENCES P2                              15

 QUESTION 8 (Start on a NEW page)

 A group of learners investigate the effect of decreasing the distance between an
 object and a convex lens on the height of the image formed. They place the object
 at different positions from the lens as shown in the diagrams below and measure
 the height of the image formed at each position.

 Diagram A: Object beyond 2F                 Diagram B: Object between F and 2F

 Diagram C: Object between F and lens

 8.1 Besides the larger height of the image formed in diagram C, write down TWO
     other properties of the image formed in diagram C.                                    (2)

 8.2 For this investigation write down:

       8.2.1    The independent variable                                                   (2)

       8.2.2    TWO precautions that the learners must take to ensure a fair test          (2)

 The learners conclude that: “As the distance between the lens and the object
 decreases the height of the image increases.”

 8.3 Is the learners’ conclusion generally TRUE? (YES or NO)

       Explain the answer.                                                                 (2)

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16                            TECHNICAL SCIENCES P2                     (EC/SEPTEMBER 2018)

 8.4 In the diagram below the focal length (F) of the lens is 30 mm. Draw a ray
     diagram to determine the position of the image formed when an object of
     height 20 mm is placed at 2F.

                                                                                       (4)
                                                                                      [12]

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(EC/SEPTEMBER 2018)                       TECHNICAL SCIENCES P2                                17

 QUESTION 9 (Start on a NEW page)

 9.1 The diagram below shows the spectrum obtained during the dispersion of
     white light.

           Violet
                         Indigo      X       Green      Yellow     Orange        Red

       9.1.1    Define the term dispersion                                                     (2)

       9.1.2    Write down the name of the colour of light represented by X.                   (1)

       9.1.3    Which colour of visible light has the highest frequency?                       (1)

       A photon of a light wave has 7,0 x 10-19 J of energy.

       9.1.4    Define the term photon.                                                        (2)

       9.1.5    Calculate the wavelength of the wave.                                          (5)

 9.2 An electromagnetic wave is defined below. Write down the missing word.

       An electromagnetic wave is a changing … field and a changing magnetic field
       mutually perpendicular to each other and the direction of propagation of the
       wave.                                                                                   (1)

 9.3 Four of the seven electromagnetic radiations are listed below.

         Ultraviolet rays      Microwaves          Visible light      Infra-red rays

       Write down the NAME of electromagnetic radiation from the list given above
       that:

       9.3.1    Is used in night-vision devices                                                (1)

       9.3.2    Leads to skin damage when one is over exposed to sunlight.                     (1)

       9.3.3    Has photons with lowest energy                                                 (1)

 9.4 Name THREE electromagnetic radiations NOT shown in the list given in
     QUESTION 9.3 above.                                                                       (3)
                                                                                              [18]

                                                                                TOTAL:        150

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18                                         TECHNICAL SCIENCES P2                      (EC/SEPTEMBER 2018)

 4.3   INFORMATION SHEETS – PAPER 2

       TABLE 1: PHYSICAL CONSTANTS

                 NAME                                SYMBOL                  VALUE
       Standard pressure                                          1,01 x 105 Pa
                                                       p
       Standard temperature                            T          273 K
       Speed of light in a vacuum                      c           3,0 x 108 m·s-1
       Planck's constant                               h           6,63 x 10-34 J·s

       TABLE 2: WAVES, SOUND AND LIGHT

       vf                                                1
                                                      T
                                                           f
                               c
       E  hf     or E  h
                               

       TABLE 2: FORMULAE

       Eθcell  Eθcathode  Eθanode

       Eθcell  Ereduction
                 θ
                            Eθoxidation

       Eθcell  Eθoxidisingagent  Ereducing
                                    θ
                                             agent

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(EC/SEPTEMBER 2018)
                                                Downloaded from hlayiso.com         TECHNICAL SCIENCES P2                                                                                                 19

                                                                         TABLE 3: THE PERIODIC TABLE OF ELEMENTS
                                                        5
       1            2                                                                                                                                   13        14             15       16          17         18
                                3           4                        6          7      8      9                    10         11           12
      (I)          (II)                                                              Atomic number                                                     (III)     (IV)            (V)     (VI)        (VII)      (VIII)
                                                    KEY/SLEUTEL                        Atoomgetal
       1                                                                                                                                                                                                           2
2,1    H                                                                                                                                                                                                          He
       1                                                                                         29                                                                                                                4
                                                                                                            Symbol
       3             4                                       Electronegativity             1,9   Cu         Simbool
                                                                                                                                                          5           6           7           8            9      10
1,0    Li    1,5    Be                                      Elektronegatiwiteit                  63,5                                            2,0     B     2,5    C    3,0    N    3,5    O    4,0    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      Co   1,8
                                                                                                    Ni       1,8        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      Rh   2,2
                                                                                                    Pd       2,2        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

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                               20                             TECHNICAL SCIENCES P2             (EC/SEPTEMBER 2018)

                                                     TABLE 4A: STANDARD REDUCTION POTENTIALS
                                                            Half-reactions                 Eθ (V)
                                      F2(g) + 2e                ⇌      2F                + 2,87
                                         3+
                                      Co + e                    ⇌      Co2+                 + 1,81
                                                 +
                                      H2O2 + 2H +2e             ⇌      2H2O                  +1,77
                                            
                                      MnO + 8H + 5e+            ⇌         2+
                                                                        Mn + 4H2O            + 1,51
                                             4
                                      Cℓ2(g) + 2e               ⇌     2Cℓ                  + 1,36
                                      Cr2O 72  + 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 3 + 4H+ + 3e          ⇌     NO(g) + 2H2O          + 0,96
                                      Hg2+ + 2e                 ⇌     Hg(ℓ)                 + 0,85
                                      Ag+ + e                   ⇌     Ag                    + 0,80
                                      NO 3 + 2H+ + e           ⇌     NO2(g) + H2O          + 0,80
                                        3+
                                      Fe + e                    ⇌     Fe2+                  + 0,77
                                      O2(g) + 2H+ + 2e          ⇌     H2O2                  + 0,68
                                      I2 + 2e                   ⇌     2I                   + 0,54
                                      Cu+ + e                   ⇌

                                                                                                                Increasing reducing ability/
                                                                       Cu                    + 0,52

Increasing oxidising ability
                                      SO2 + 4H+ + 4e            ⇌     S + 2H2O              + 0,45
                                      2H2O + O2 + 4e            ⇌     4OH                  + 0,40
                                      Cu2+ + 2e                 ⇌     Cu                    + 0,34
                                      SO 24  + 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

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### Page 21

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                               (EC/SEPTEMBER 2018)                  TECHNICAL SCIENCES P2                                                            21
                                                           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
                                         2+
                                      Sr + 2e                         ⇌      Sr                    2,89
                                      Ca2+ + 2e                       ⇌      Ca                    2,87
                                          +
                                      Na + e                          ⇌      Na                    2,71
                                      Mg2+ + 2e                       ⇌      Mg                    2,36
                                      Aℓ + 3e
                                         3+                           ⇌      Aℓ                    1,66
                                      Mn2+ + 2e                       ⇌      Mn                    1,18
                                         2+
                                      Cr + 2e                         ⇌      Cr                    0,91
                                      2H2O + 2e                       ⇌      H2(g) + 2OH          0,83
                                          2+
                                      Zn + 2e                         ⇌      Zn                    0,76
                                      Cr3+ + 3e                       ⇌      Cr                    0,74
                                          2+
                                      Fe + 2e                         ⇌      Fe                    0,44
                                      Cr3+ + e                        ⇌      Cr2+                  0,41
                                          2+
                                      Cd + 2e                         ⇌      Cd                    0,40
                                      Co2+ + 2e                       ⇌      Co                    0,28

Increasing oxidising ability
                                         2+
                                      Ni + 2e                         ⇌      Ni                    0,27

                                                                                                                      Increasing reducing ability/
                                      Sn2+ + 2e                       ⇌      Sn                    0,14
                                          2+
                                      Pb + 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
                                          2+
                                      Cu + 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
                                      Cr2O 72  + 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

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