NCERT Class XII Chemistry
Chapter - Electrochemistry
Questions with Solutions
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Question : 33
Total: 32
Explain how rusting of iron is envisaged as setting up of an electrochemical cell.
Solution:
The following reactions take place at the surface of iron metal whichacts as an electrochemical cell.
F e ( s ) → F 2 + ( a q ) + 2 e −
O 2 ( g ) + 4 H + ( a q ) + 4 e − → 2 H 2 O ( l )
– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
2 F 2 + ( a q ) + 2 H 2 O ( l ) + 1 ∕ 2 O 2 ( g ) → F e 2 O 3 ( s ) + 4 H + ( a q ) + 4 H + ( a q )
– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – C O 2 + +
H 2 O + C O 2 – – – – – – – ▶ H 2 C O 3 ⇌ 2 H + + C O 3 2 –
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