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Electrochemistry — Chemistry STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceChemistryElectrochemistry5 Marks
Question
Consider the and answer the following questions.
  1. Cell $'A\ ’$ has $E_{Cell}= 2V$ and Cell $'B\ ’$ has $E_{Cell} = 1.1V$ which of the two cells $'A\ ’$ or $'B\ ’$ will act as an electrolytic cell. Which electrode reactions will occur in this cell?
  2. If cell $'A\ ’$ has $E_{Cell}= 0.5V$ and cell $'B\ ’$ has $E_{Cell}= 1.1V$ then what will be the reactions at anode and cathode?
✓

Answer

  1. Cell ‘B’ will act as electrolytic cell as it has lower emf
$\therefore$ The electrode reactions will be:
$\text{zn}^{2+}+2\text{e}^{-}\xrightarrow{\ \ \ \ \ \ \ \ \ \ \ }\text{zn}\ \ \text{ at cathode}$
$\text{Cu}\xrightarrow{\ \ \ \ \ \ \ \ \ \ \ }\text{Cu}^{2+}+2\text{e}^-\ \ \text{ at anode}$
  1. Now cell $'B\ ’$ acts as galvanic cell as it has higher emf and will push electrons into cell $‘A’.$
The electrode reaction will be:
$\text{at cathode}\ \ \text{ zn}\xrightarrow{\ \ \ \ \ \ \ \ \ \ \ }\text{zn}^{2+}+2\text{e}^{-}$
$\text{ at anode}\ \ \ \text{Cu}^{2+}+2\text{e}^-\xrightarrow{\ \ \ \ \ \ \ \ \ \ \ }\text{Cu}$

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