NEET 2024: Important Questions Electrochemistry

1. Redox Reactions:

One element loses electrons (oxidation), while another gains them (reduction). It's an electron exchange party! Picture it as a cosmic game where atoms pass around electrons, changing their charge and forming new substances. Like a teamwork tango, this dance creates electricity in batteries and powers many chemical reactions. Understanding redox reactions unveils the dynamic partnership between atoms, showcasing how their electron shuffle drives the fascinating chemistry behind powering our world and making reactions click.

2. Conductance in Electrolytic Solutions:

Electrolytes are like partygoers that carry electrical charges through a solution. When these charged guests move, they create a conductive pathway. It's like a dance floor where charged particles groove, allowing electric current to flow. Understanding conductance in electrolytic solutions unveils the secret dance of ions, a crucial concept in batteries, electroplating, and various chemical processes. It's like decoding the rhythm of charged particles, orchestrating a harmonious symphony in the world of chemistry.

3. Specific and Molar Conductivity:

Specific conductivity measures how well a solution conducts electricity. It's like checking how smoothly a relay race baton passes between team members. Molar conductivity, on the other hand, scales this teamwork to a single particle, showcasing each player's individual contribution. As concentration changes, conductivity evolves – it's like adjusting the team size and watching their performance shift. Understanding this conductivity dance sheds light on how solutions behave electrically, crucial for designing efficient batteries and comprehending electrochemical processes.

4. Kohlrausch’s Law:

It says every ion contributes uniquely to the solution's conductivity like each hero adding specific powers to a team. By measuring the individual contributions, we get a sneak peek into the ion team's strengths. It's like decoding the chemistry of ions in a solution – some ions are speedy sprinters, while others are slow and steady. Understanding Kohlrausch's Law unveils the superhero roles of ions in conducting electricity, a key insight for mastering the electrochemical orchestra in chemistry.

5. Electrolysis and Law of Electrolysis:

Electrolysis is a trick where we use electricity to turn substances into something entirely new. The Law of Electrolysis, a magical rule discovered by Faraday, guides this transformation. It says the amount of substance changed is directly proportional to the electric current flowing through. Picture it as turning water into hydrogen and oxygen with a wave of an electric wand!

6. Dry Cell - Electrolytic Cell and Glavanic Cell:

Dry Cell, Electrolytic Cell, and Galvanic Cell" in the "Electrochemistry" chapter is like getting to know three unique characters in the chemistry universe. A Dry Cell is your portable power buddy, like the battery in your gadgets. Electrolytic Cell is the magician's stage, where electricity transforms substances through electrolysis. Galvanic Cell, on the other hand, is the power generator – like a mini power plant producing electricity from chemical reactions. 

7. Lead Accumulator:

Picture it as a trusty power bank for your car! This battery, also known as a lead accumulator, stores and releases energy through reversible chemical reactions. When you start your car, it's like unleashing stored power to kick things into action. Understanding the lead accumulator is like peeking into the secret behind your car's starting and charging system. 

8. EMF of a Cell:

It's the electrical push that makes reactions happen. Imagine it as the motivational force driving a team. The EMF (Electromotive Force) of a cell tells us how keen these chemical teammates are to make reactions go. It's like checking the enthusiasm level of players before a game. Understanding the EMF of a cell unveils the electrical motivation behind chemical reactions, helping us gauge the energetic partnership within a cell's chemistry team.

9. Standard Electrode Potential:

It measures how eager elements are to play in the chemical world. Picture it as a leaderboard where each element showcases its enthusiasm for gaining or losing electrons. More positive potential means high enthusiasm, and vice versa. It's like watching a chemistry talent show unfold! 

10. Relation between Gibb’s energy change and EMF of a Cell:

EMF is the electrical push in a cell, and Gibbs's energy change is the measure of how much energy is released or absorbed during a reaction. If EMF is positive, the reaction is energetically thrilled.

11. Fule Cells; Corrosion:

Fuel cells are like clean, efficient powerhouses converting fuel into electricity with minimal pollution – a green superhero in energy production. On the flip side, corrosion is the slow, silent villain, eating away at metals over time. It's like the rust that appears on your bicycle. Understanding fuel cells unveils a cleaner energy future, while tackling corrosion helps us protect metal treasures. Together, they showcase the dynamic balance of beneficial and harmful electrochemical reactions in our daily lives.

Important Questions for Electrochemistry

1. $ F_{2}$ gas can’t be obtained by the electrolysis of any $F^{-}$ salt because?

(a.) Fluorine is the strongest reducing agent

(b.) Fluorine is the strongest oxidizing agent

(c.) Fluorine easily combines with atmospheric $O_{2}$

(d.) All

Ans. (B)

Since Fluorine is the strongest oxidizing agent so it will destroy the electrode employed.

2. During the discharge of lead storage cell the density of sulphuric acid in the cell.

(a.) Increased

(b.)  Decreased

(c.) Remains unchanged

(d.) Initially increases and decreases subsequently.

Ans. (B)

During the discharge of the lead storage cell sulphuric acid is consumed. Its concentration decreases therefore its density decreases.

3. The number of faradays required to produce one mole of water from a hydrogen - oxygen fule cell containing aqueous alkali as electrolyte is?

(a.) 1

(b.) 3

(c.) 2

(d.) 4

Ans. (C)

This is based on the application of Faraday’s law of electrolysis. One mole of water can be obtained by the combination of a $H_{2} and \frac{1}{2}$ mole of oxygen which maybe produced by the passage of 2 Faradays.

4. The amount of electrical energy produced during the passage of 2 ampere current for 150 s under a potential of 125 volt is 

(a.) 9.375 kJ

(b.) 37.5 kJ

(c.) 75 kJ

(d.) 3.75 kJ

Ans. (B)

Explanation:

$Electrical energy = Charge \times  Potential 

Charge "Q" = Current (I) \times Time (t)

Hence, electrical energy = i \times v \times t  = 2 \times 150 \times 125 = 37.5 kJ $

5. Which statement is not correct for Kohlrausch’s law?

(a.) The law is valid at infinite dilution

(b.) The law is valid for weak electrolytes only

(c.) The basis of law is independent migration of ions

(d.) None of the above

Ans. (B)

The law is valid for both weak and strong electrolytes.

Important Topics from Electrochemistry

• Redox Reactions

• Specific and Molar Conductivity

• Kohlrausch’s Law

• Variations of Conductivity with Concentration

• Conductance in Electrolytic Solutions

• Relation Between Gibbs Energy Change and EMF of a Cell

• Nernst Equation and its Application to Chemical Cells

• EMF of a cell

• Standard Electrode Potential

• Electrolysis (Faraday’s Laws)