Page 179 - Chemistry ICSE Class X
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Electrolysis                                                                                         165
          electroplating solution. When electricity is passed through the solution, the
          following reactions take place:                                              ZƵďďĞƌ ƉĂƌƟĐůĞƐ ŝŶ ůĂƚĞdž ĂƌĞ
                                                                                       ŶĞŐĂƟǀĞůLJ ĐŚĂƌŐĞĚ͘ dŚĞ ĂƌƟĐůĞͬ
                                               –
                                     2+
              At cathode:          Ni  +  2e       o        Ni                        ŽďũĞĐƚ ƚŽ ďĞ ĞůĞĐƚƌŽƉůĂƚĞĚ ǁŝƚŚ
                                 nickel ion               nickel atom                  ƌƵďďĞƌ ŝƐ ŵĂĚĞ ĂŶŽĚĞ ŝŶ ƚŚĞ
                               (from solution)         (gets deposited on the spoon)   ĞůĞĐƚƌŽůLJƟĐ ďĂƚŚ͘
              At anode:                      Ni    o       Ni 2+  +      2e –
                                            from anode      goes into solution
                       2+
              Thus, Ni  ions from the solution are reduced and Ni atoms get
          deposited on the surface of the aluminium spoon, acting as cathode. Nickel
                                                          2+
          (Ni) atoms from the anode are oxidised to form Ni  ions, which go into the
          solution.


                                                   ASSIGNMENT 3

                                                   Applications of electrolysis

             ϭ͘  EĂŵĞ ǀĂƌŝŽƵƐ ǁĂLJƐ ďLJ ǁŚŝĐŚ ƚŚĞ ƉƌŝŶĐŝƉůĞ ŽĨ ĞůĞĐƚƌŽůLJƐŝƐ ŝƐ ƵƐĞĚ ŝŶ ŝŶĚƵƐƚƌLJ͘
             Ϯ͘  ,Žǁ ĂƌĞ ŵĞƚĂůƐ ƌĞĮŶĞĚ ďLJ ƚŚĞ ĞůĞĐƚƌŽůLJƟĐ ƉƌŽĐĞƐƐ͍
             ϯ͘  ,Žǁ ŝƐ ĐŚůŽƌŝŶĞ ŵĂŶƵĨĂĐƚƵƌĞĚ ĞůĞĐƚƌŽůLJƟĐĂůůLJ͍
             ϰ͘  tƌŝƚĞ ĐŚĞŵŝĐĂů ĞƋƵĂƟŽŶƐ ĨŽƌ ƚŚĞ ƉƌŽĐĞƐƐĞƐ Ăƚ ƚŚĞ ĂŶŽĚĞ ĂŶĚ ĐĂƚŚŽĚĞ ĚƵƌŝŶŐ ĞůĞĐƚƌŽůLJƟĐ ƉƵƌŝĮĐĂƟŽŶ ŽĨ ŝŵƉƵƌĞ ĐŽƉƉĞƌ͘
             ϱ͘  EĂŵĞ ƚŚĞ ƐĂůƚƐ ƵƐĞĚ ĂƐ ĞůĞĐƚƌŽůLJƚĞ ĨŽƌ ĞůĞĐƚƌŽƉůĂƟŶŐ
                 ;ĂͿ  ŐŽůĚ                    ;ďͿ  ĐŚƌŽŵŝƵŵ
                 ;ĐͿ  ƐŝůǀĞƌ ĂŶĚ              ;ĚͿ  ĐŽƉƉĞƌ͘
             ϲ͘  ZƵďďĞƌ ŝƐ ƚŽ ďĞ ĞůĞĐƚƌŽƉůĂƚĞĚ ŽŶ ĂŶ ŽďũĞĐƚ͘ dŽ ǁŚŝĐŚ ƚĞƌŵŝŶĂů ŽĨ ƚŚĞ ďĂƩĞƌLJ ƐŚŽƵůĚ ƚŚĂƚ ŽďũĞĐƚ ďĞ ĐŽŶŶĞĐƚĞĚ͍
             ϳ͘  'ŝǀĞ ƌĞĂƐŽŶ͗
                 ;ĂͿ   ĐŝĚŝĮĞĚ ĐŽƉƉĞƌ ƐƵůƉŚĂƚĞ ŝƐ ƵƐĞĚ ĂƐ ĂŶ ĞůĞĐƚƌŽůLJƚĞ ĚƵƌŝŶŐ ƚŚĞ ƌĞĮŶŝŶŐ ŽĨ ŝŵƉƵƌĞ ĐŽƉƉĞƌ ŵĞƚĂů͘
                 ;ďͿ  ^ŽĚŝƵŵ ĂƌŐĞŶƚŽĐLJĂŶŝĚĞ ŝƐ ƉƌĞĨĞƌƌĞĚ ŽǀĞƌ ƐŝůǀĞƌ ŶŝƚƌĂƚĞ ĂƐ ƚŚĞ ĞůĞĐƚƌŽůLJƚĞ ĨŽƌ ƐŝůǀĞƌ ĞůĞĐƚƌŽƉůĂƟŶŐ͘


                                      Let us Answer Some More Questions


             1.  What are electrolytes and nonelectrolytes?
             2.  Classify the following into electrolytes and nonelectrolytes:
                (a)  silver nitrate                          (b)  cane sugar
                 (c)  potassium chloride                     (d)  glucose.
             3.  &GſPG GNGEVTQN[UKU  9JKEJ V[RG QH GNGEVTKE EWTTGPV KU WUGF KP GNGEVTQN[UKU!

             4.  Describe the experimental set-up used for electrolysis, with the help of a labelled diagram.
             5.  What is the nature of reaction at
                (a) anode,
                 (b)  cathode, in an electrolytic cell?
             6.  Write the reactions which take place when molten sodium chloride is electrolysed by using platinum electrodes.
             7.  (a)  Describe the activity series for metals and their ions.
                 (b)  Write the symbols of the cations,

                    (i) which get easily discharged at cathode during electrolysis.
                    (ii) which do not get easily discharged at the cathode during electrolysis.
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