In the button cells widely used in watches and other devices the following reaction takes place:
Zn(s) + Ag2O(s) + H2O(l) \(\rightarrow\) Zn2+(aq) + 2Ag(s) + 2OH- (aq)
Determine \(\triangle _rG^\ominus\) and \(E^\ominus\) for the reaction.
Zn(s) + Ag2O(s) + H2O(l) \(\rightarrow\) Zn2+(aq) + 2Ag(s) + 2OH- (aq)
Determine \(\triangle _rG^\ominus\) and \(E^\ominus\) for the reaction.
Solution and Explanation
Zn(s)→ Zn2+(aq)+2e- ; \(E^\ominus\) = 0.76 V
Ag2O(s)+H2O(l)+2e- → 2Ag(s)+2OH-(aq) ; \(E^\ominus\) = 0.344 V
____________________________________________________________________
Zn(s)+ Ag2O(s)+H2O(l)→ Zn2+(aq)+2Ag(s)+2OH-(aq); \(E^\ominus\) = 1.104 V
\(E^\ominus\)= 1.104 V
We know that,
\(\triangle_rG^\ominus=-nFE^\ominus\)
= - 2 × 96487 × 1.04
= - 213043.296 J
= - 213.04 kJ
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Concepts Used:
Electrolysis
Electrolysis:
Electrolysis is the process by which an element is decomposed and undergoes some chemical change under the influence of any electric current. The first-ever electrolysis was executed out by Sir Humphrey Davey in the year 1808. Electrolysis can occur in both Galvanic cells and Electrolytic cells.
Applications of Electrolysis:
- Electrolytic cells are used for the production of Hydrogen and Oxygen gas from water.
- They are used for the large-scale production of pure metals like sodium, copper, magnesium, etc.
- They are used to extract Aluminium from Bauxite.
- Electrolytic cells are used for electroplating, a process by which a thin protective layer of one metal is formed over another metal, mostly for protection.
- Electrolysis is used for the electrorefining of non-ferrous metals.
Read More: Products of Electrolysis