Chemistry · Redox Equilibrium · NEET
Zinc is the anode. The anode is where oxidation happens, and zinc loses electrons: Zn goes to Zn2+ plus 2 electrons. Copper is the cathode, where reduction happens: Cu2+ plus 2 electrons goes to Cu. A simple check for NEET: in any galvanic cell the metal that is higher (more reactive) in the activity series becomes the anode. Zinc is more reactive than copper, so zinc is the anode.
Zinc atoms have a stronger tendency to lose electrons than copper. So zinc atoms leave the rod as Zn2+ ions and enter the ZnSO4 solution, making the zinc rod slowly lose mass. The electrons travel through the wire to the copper side, where Cu2+ ions from CuSO4 pick up those electrons and become copper metal, which sticks to the copper rod. So the zinc electrode loses mass and the copper electrode gains mass.
Electrons flow through the outer metallic wire from the zinc (anode) to the copper (cathode). Conventional current flows the opposite way, from copper to zinc, because current direction is defined opposite to electron flow. Inside the cell, charge is carried not by electrons but by ions moving through the solution and the salt bridge.
No. Electrons never travel through the salt bridge or the solution. Electrons only move through the outer wire. The salt bridge carries ions (like K+ and Cl- or NH4+ and NO3-) to keep both solutions electrically neutral. This is a very common NEET trap - the wire carries electrons, the salt bridge and solution carry ions.
About 1.1 V at 298 K when both Zn2+ and Cu2+ solutions are 1 M. You get it from E of cell = E cathode minus E anode = 0.34 V minus (minus 0.76 V) = 1.10 V. Because the EMF is positive, the reaction is spontaneous, which is why the cell produces current on its own.
If you dip a zinc rod straight into copper sulphate, electrons pass directly from zinc to Cu2+ and only heat comes out - no usable electricity. In a Daniell cell you separate the two metals into different beakers, so the same reaction is forced to send electrons through an external wire. That indirect transfer is what gives you electrical energy you can use.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
At the anode (zinc): Zn goes to Zn2+ plus 2 electrons (oxidation). At the cathode (copper): Cu2+ plus 2 electrons goes to Cu (reduction). Overall: Zn plus Cu2+ goes to Zn2+ plus Cu.
Zn(s) | Zn2+(aq) || Cu2+(aq) | Cu(s). The anode is written on the left, the double line stands for the salt bridge, and the cathode is on the right.
A U-tube filled with a solution of KCl or NH4NO3 set into a jelly with agar-agar. It connects the two solutions and lets ions move, but stops the two solutions from mixing.
As the cell works, the anode side builds up positive Zn2+ and the cathode side loses positive Cu2+. The salt bridge feeds ions in to keep both sides electrically neutral, so the current keeps flowing. Without it the cell stops almost at once.
It is a galvanic (voltaic) cell. It changes chemical energy into electrical energy on its own because the reaction is spontaneous, with a positive EMF of about 1.1 V.
