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The diagram below shows a set up which was used by student to investigate effect of electricity on solid Molten Lead (II) Bromide. Study it...

The diagram below shows a set up which was used by student to investigate effect of electricity on solid Molten Lead (II) Bromide. Study it and answer the questions that follow.

(a) (i) State and explain the observation at the anode when the switch is switched on.
(ii) What precaution should be taken when carrying out this experiment?
(iii) Write the equation of the reaction taking place at the Anode.
(iv) Why are graphite electrodes used in the experiment?
(v) On the diagram, indicate the direction of flow of electrons.
(vi) The students noted that the bulb only produced light after the Lead (II) Bromide had melted. Explain this observation.
(b) State the difference in conduction of electric current between Molten Lead (II) Bromide and Lead Metal.
(c) Explain why it is not advisable to store Copper (II) Sulphate solution in a can made of Zinc metal.
(d) State two applications of electrolysis.

Answers

(a) (i) Brown fumes form at the anode.
- Bromide ions in the molten lead (II) bromide are oxidized to bromine gas which is brown.
(ii) Experiment should be carried out in a fume chamber or in the open because bromine gas is poisonous.

(iv) - They are good conductors of heat.
- They are inert.
(v) On the diagram arrow point from negative terminal of cell to cathode.
(vi) In solid state led (II) bromide is a poor conductor of electricity because it does not have mobile ions in molten state lead (II) bromide is a good conductor. It has no mobile ions.
(b) PbBr conducts because of mobile ions.
Pb metal conducts due to mobile electrons.
(c) The zinc container will be corroded because zinc is more reactive than copper. Zinc container will react with copper (II) sulphate solution to form zinc sulphate.
(d) - Extraction of meal of Na, Ma, Al.
- Purification of metal of copper.
- Electroplating metal to prevent corrosion or improve appearance.
- Manufacture of chemicals of Cl, NaOH and H_2(g).

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sharon kalunda answered the question on March 27, 2019 at 10:21

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