JEE Advanced Electrochemistry Important Questions

The Nernst equation, which is used in a wide variety of applications such as determining solubility of products, Potentiometric Titrations, or even measuring the pH of a substance, gives us the relationship between standard electrode potential of a particular electrode and its electrode potential in other different situations. The equation also helps predict the spontaneity of an electrochemical reaction, or to calculate the Gibbs free energy. 

Example:

Consider the following chemical reaction:

Mn+ (aq) + ne– → M(s)

Then, the Nernst equation can be stated as:

E \[\frac{(Mn+)}{(M)}\] =  E° \[\frac{(Mn+)}{(M)}\] − RTnF ln\[\frac{(M)}{(Mn+)}\]

To know more about the application of the formula as well as other key details, we recommend you to check our article dedicated to the Nernst equation.

A cell that is capable of generating electricity from a chemical process, or one that gives rise to a chemical change by passing electricity is known as an electrochemical cell. These cells work upon the principles of a redox (or Oxidation-Reduction) process. Depending upon the way they’ve been built as well as the way in which they function, there are different types of electrochemical cells such as:

1. Electrolytic Cell: In an electrolytic cell, conversion from electrical energy into chemical energy takes place, with the help of a non-spontaneous reaction.

2. Galvanic Cell: Exactly the opposite of electrolytic cell, a galvanic cell uses redox reaction to convert chemical energy into electrical energy.

Students wanting to take an in depth look about the topic can click here for the dedicated article on Electrolysis. Before jumping directly into the two laws, let's first understand a few basic terms. An electrolyte is any liquid solution (usually a salt solution of a metal) that is capable of allowing the flow of charges (i.e. electrons). Electrolysis is essentially the use of electrical energy to bring about a chemical change. An electrode is nothing but a point where electrons either leave or enter the electric circuit. Now moving on to the first law, it can be stated as: “The mass of a substance deposited at any electrode is directly proportional to the amount of charge passed.” Thus,

m ∝ Q ----------(1)

where m = mass

Q = Amount of charge passed

Further, the second law can be stated as: “the mass of a substance deposited at any electrode on passing a certain amount of charge is directly proportional to its chemical equivalent weight”

Mathematically, it would be expressed as:

w ∝  E

where w = mass of the substance

and E = equivalent weight

Like the name suggests, a salt bridge basically acts as the ‘bridge’ between two half cells, one representing the oxidation half while the other representing reduction half. Alternatively, it can also be called as a junction that connects the anodic and cathodic compartments of an electrolytic solution. A salt bridge is usually made up of strong electrolytes like that of KCl, AgNO₃, and more. Salt bridges are generally more common in galvanic cells like voltaic cells or Daniel cells. The absence of a salt bridge will give rise to accumulation of negative charges on one half of a cell, and positive charges on the other half, which eventually brings the reaction to a halt.

As you can probably tell by now, Vedantu offers dedicated articles not just for individual topics from each subject, but also for many of the important laws, derivations, equations, and theories that are found within the chapter. This can help the students by providing them with everything that they need in order to fully master the particular concept and make sure that they do not make any errors while solving a question based on it. With that, we have successfully solved some important questions based on Electrochemistry and we sincerely hope students are feeling confident about it. Just for a reminder, students must note that a good score in so many tests should not make them complacent, while a poor score should not discourage them either.