Asked in NUMS 2019 (cancelled sitting) 2019Moderate

What is the cell reaction ofZn(s) | Zn2+(aq) 1M | Ni2+(aq) 1M | Ni(s)Zn2+(aq) + 2e- -> Zn(s), Eo = -0.76 VNi2+(aq) + 2e- -> Ni(s), Eo = -0.25 V

Correct answer: A. Ni2+ + Zn -> Zn2+ + Ni

  • A. Ni2+ + Zn -> Zn2+ + Ni
  • B. Zn2+ + Ni -> Ni2+ + Zn
  • C. Zn2+ + Ni2+ -> Zn + Ni
  • D. Zn + Ni -> Zn2+ + Ni2+

Explanation

In the given cell, Zn is oxidized to Zn2+ ions, and Ni2+ ions are reduced to Ni atoms. The anode is Zn, and the cathode is Ni. The electrons flow from the Zn electrode to the Ni electrode through the wire and the salt bridge. The overall reaction is: Zn(s) + Ni2+ (aq) → Zn2+ (aq) + Ni(s)

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About Redox Reactions

Redox reactions involve oxidation and reduction occurring together, with electrons transferred between species or oxidation numbers changing. The topic covers assigning oxidation states, identifying oxidizing and reducing agents, balancing redox equations by oxidation number or half-reaction methods, and connecting chemical changes with galvanic and electrolytic cells.

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