Test: Electrochemical cells and Electrode Potential - JEE MCQ

The correct answer is Option A.

For a good salt bridge, the velocities of ions should be the same. If the velocities are not the same, then the ions would not be able to neutralize the charge equally in both half cells. Consequently, an opposite force would be developed that restricts the flow of current. For KNO3, the velocities of K+and NO3- are nearly the same. Therefore, it is used to make salt bridges

The correct answer is Option D
oxidation
The reaction at the anode is oxidation and that at the cathode is reduction. The electrons are supplied by the species getting oxidized. They move from anode to the cathode in the external circuit.

The electrode having lower reduction potential will have lesser tendency to gain electrons.
i.e. act as anode.

Cell constant

When


The half cell reaction

In the Daniell cell, copper and zinc electrodes are immersed in a solution of copper(II) sulphate and zinc sulphate, respectively.
At the anode (negative electrode), zinc is oxidised per the following half reaction.
Zn(s) ⟶ Zn²⁺(aq) + 2e⁻
At the cathode (positive electrode), copper is reduced per the following reaction.
Cu²⁺ (aq) + 2e⁻⟶ Cu(s)
Overall cell reaction is
Zn(s) + Cu²⁺(aq) ⟶ Zn²⁺(aq) + Cu(s)
These processes result in the accumulation of solid copper at the cathode and the corrosion of the zinc electrode into the solution as zinc cations. Hence, the correct option is (1).