Q2 of 7 Page 84

When acidified copper sulphate solution is electrolyzed oxygen is obtained at the anode. What arrangements are to be made for this? Find the element deposited at the cathode.

Take copper sulphate (CuSO4) in a beaker. Add some acid (H2SO4) to it and make a copper solution. Immerse two carbon rods in a beaker. Connect a battery to the rods. Oxidation occurs at anode and reduction occurs at the cathode. And we can observe that oxygen is produced at the anode.

4OH-(aq) 2H2O(l) + O2(g) + 4e-


Or H2O(l) 4H+(aq) + O2(g) + 4e-


And at cathode, copper will deposit due to conversion of Cu2+ ions to Cu.


Cu2+(aq) + 2e- Cu(s)


More from this chapter

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3

You are given a solution of AgNO3, a solution of MgSO4, an Ag rod and an Mg ribbon. How can you arrange a Galvanic cell using these? Write down the reactions taking place at the cathode and the anode.

 1

Keep two carbon rods immersed in a copper sulphate solution. Then pass electricity through the soon.

(i) At which electrode does a colour change occur-anode or cathode?


(ii) Is there any change in the blue colour of the copper sulphate solution?


(iii) Write down the chemical equations for the changes occurring here.

 3

How many Galvanic cells can be made by using the metals Ag, Cu, Zn, and Mg? When Galvanic cells are made using the metals given, what will be the nature of reactions in each cell? (Reactivity: Mg>Zn>Cu>Ag).

 4

You are familiar with some materials which are used in various secondary cells.

Make a list of different types of chemical cells. Analyse how they influence the environment.