Wednesday, 21 January 2015

6.6 The Electrochemical Series

Electrochemical series
■ Electrochemical series

A series of elements arrangement according to the order of decreasing tendency to release electrons.

Element located at higher position in the electrochemical series:
More electropositive
Has a greater tendency to form cations by donating electrons
More reactive
■ Electrochemical series can be constructed based on:

The potential difference between two metals in the voltaic cell.
Metals that further apart in the electrochemical series produce a higher voltage that metals which are close to each other.

The displacement of metals by another more reactive metals from its salt solution.
The metal which is more electropositive will displace the less electropositive metal from its salt solution.
Example: Displacement of copper, Cu, from copper(II) nitrate solution by zinc.
Chemical equation: ZN(s) + CU(NO3)2(aq) → Zn(NO3)2(aq) + Cu(s)
Nitrate ion, NO-3 does not take part in the chemical reaction
Thus, ionic equation can be written as:Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)
Laboratory Activity 6.6.1: Constructing the electrochemical series based on the potential difference between two metals
Laboratory Activity 6.6.2: To construct the electrochemical series based on the displacement of metals
■ This video contains information on the electrochemical series.



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