Salt Bridge
o These electrodes behave as terminal to hold the electrons. o The two electrodes are connected via wire. o
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A salt bridge is placed between the two beakers. This provides a path for the movement of ions from one beaker to the other in order to maintain electrical neutrality.
Zinc electrode gets oxidized and hence releases electrons that flow through the wire towards the copper electrode.
The copper( II) sulphate solution releases copper ions Cu 2 +.
o At the anode:
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Oxidation---------------- loss of electrons. Zn-- > Zn 2 + + 2e-
At cathode,
Reduction-------------gain of electrons.
Cu 2 + + 2e--- > Cu
Zinc atoms being more reactive have a greater tendency to lose electrons than that of copper. The electrons in this cell moves from zinc anode to copper cathode through the wire connecting the two electrodes in the external circuit
A bulb placed within this circuit will glow and a voltmeter connected within this circuit will show deflection.
o The net reaction of this cell is the sum of two half-cell reactions. Zn( s) + Cu 2 +( aq)-- > Zn 2 +( aq) + Cu( s)
In a Daniel cell a salt bridge is placed between the two beakers containing a solution of zinc sulphate( ZnSO4) and a solution of copper( II) sulphate respectively. This provides a path for the movement of ions from one beaker to the other in order to maintain electrical neutrality.
Salt Bridge