FAQ ; oxidation and reduction 1

SPM Frequently Ask Question :

TOPIC : OXIDATION AND REDUCTION

TRANSFER OF ELECTRONS AT A DISTANCE

You should study on these

 (minimum)

• 1.       The function of sulphuric acid in u-tube

• 2.       Show the direction of electron flow at connecting wire

• 3.       State the colour change of solutions (oxidizing agent and reducing agent)

• 4.       Name the oxidizing agent and reducing agent

• 5.       State type of reaction that  occur in electrodes

• 6.       State the change in the oxidation number of oxidizing agent and reducing agent

• 7.       Write half equation

• 8.       Write the overall equation for the reaction

  example :

5      Diagram 5 shows the apparatus set-up to study the reaction involving the transfer   of   electron at  a distance.

                Rajah 5 menunjukkan susunan radas untuk mengkaji tindak balas yang melibatkan   pemindahan elektron pada satu jarak.

 

    (i)        What is the function of dilute sulphuric acid?

                Apakah fungsi asid sulfurik cair?                             

                                To allow the flow of ions

                                                                         [1 mark]

                                                                                                                                               

 (ii)      In Diagram 5.1, indicate the direction of electron flow by using an arrow.

             Dalam Rajah 5.1, tunjukkan arah pengaliran elektron dengan menggunakan satu

          anak panah.

            as Shown in the diagram                                                                                                                                                                                                                                           [1 mark]

 (iii)        State the colour change for acidified potassium manganate(VII) solution.

                Nyatakan perubahan warna bagi larutan kalium manganat(VII) berasid.           

    Purple to colourless

                                                                                                         [1 mark]

* perubahan warna ; nyatakan warna bahan sebelum dan selepas tindakbalas berlaku

(iv)        Name the oxidizing agent for the reaction.

                Namakan agen pengoksidaan bagi tindak balas tersebut.

              

               Acidified potassium manganate (VII) solution/  manganate(VII) ions

                                                                                                                         [1 mark]

                (v)           Determine the type of reaction that occur at electrode X.

                                Nyatakan jenis tindak balas yang berlaku di elektrod X.

                                Oxidation

     [1 mark]

                                                                                                                                               

(vi)         What is the change in the oxidation number of Iron?

                                Apakah perubahan nombor pengoksidaan bagi Ferum?              

       +2  to  +3                                                                                                 [1 mark]

                     * perubahan no.pengoksidaan  ; nyatakan no. pengoksidaan bahan sebelum dan selepas  
                       tindakbalas berlaku

 

            vii)          Write down the half equation at for the reaction at electrode X.

Tuliskan persamaan setengah bagi tindak balas di elektrod X.

Fe²⁺       →           Fe³⁺  +  e-                                                                                                                             [1 mark]