In a Daniell Cell
A. Current flows from zinc electrode to copper electrode
B. Electrons flow from zinc electrode to copper electrode
C. Cell potential depends on size of electrodes used.
D. Electrons flow from copper electrode to zinc electrode.
E. Copper ions move towards cathode and zinc ions move away from anode
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → B and E only
In the Daniell cell, Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s), zinc is the anode (oxidation, Zn → \( \ce{Zn^{2+}} \) + 2e−) and copper is the cathode (reduction, \( \ce{Cu^{2+}} \) + 2e− → Cu):
\( \ce{Zn(s) + Cu^2+(aq) -> Zn^2+(aq) + Cu(s)} \) E°cell = 1.10 V
(A) Current flows from zinc electrode to copper electrode — Incorrect. Current flows opposite to electron flow, that is from Cu to Zn in the external circuit.
(B) Electrons flow from zinc electrode to copper electrode — Correct. Electrons released by zinc travel through the wire to the copper electrode.
(C) Cell potential depends on size of electrodes used. — Incorrect. Ecell depends on the nature of the electrodes, ion concentrations and temperature (Nernst equation), not on electrode size; size affects only the current that can be drawn.
(D) Electrons flow from copper electrode to zinc electrode — Incorrect. This is the reverse of (B); it happens only when an external potential greater than 1.1 V is applied.
(E) Copper ions move towards cathode and zinc ions move away from anode — Correct. \( \ce{Cu^{2+}} \) ions move to the copper cathode where they are deposited, and \( \ce{Zn^{2+}} \) ions formed at the anode move away into the solution.
NCERT (2026-27 edition):
Electrochemical Cells – “(i) Electrons flow from Zn rod to Cu rod hence current flows from Cu to Zn. (ii) Zn dissolves at anode and copper deposits at cathode.”