Electrochemistry NEET Questions: Answer Key, pdf
Electrochemistry NEET questions cowl key subjects like electrochemical cells, Nernst equation, electrolysis, and conductance. These questions attention on knowledge redox reactions, galvanic and electrolytic cells, Faraday’s laws, and standard electrode potentials. The NEET exam commonly checks candidates’ capacity to use concepts in solving numerical troubles, balancing equations, and calculating cell potentials. Mastery of those subjects is important for scoring properly in the chemistry section of NEET, making electrochemistry an essential bankruptcy for aspirants.
- Introduction to Electrochemistry
- Download: Electrochemistry
- Electrolytic Cells: Electrochemistry
- Galvanic (Voltaic) Cells: Electrochemistry
- Nernst Equation: Electrochemistry
- Electrode Potential and Electrochemical Series
- Conductance and Molar Conductivity
- Electrochemical Cells and Gibbs Free Energy
- Batteries and Fuel Cells: Electrochemistry
- FAQs about Electrochemistry
Introduction to Electrochemistry
Electrochemistry is a important topic in NEET, encompassing the have a look at of chemical reactions that involve the switch of electrons. It bridges the space among chemistry and energy, focusing on principles like redox reactions, electrochemical cells, widespread electrode potentials, and Nernst equation. NEET aspirants need to understand the basics of galvanic cells, electrolytic cells, and their packages, inclusive of in electroplating and batteries. Mastering Electrochemistry now not simplest enhances trouble-fixing abilties however also strengthens the draw close of thermodynamics and kinetics. Regular exercise of NEET-style questions on Electrochemistry allows college students build conceptual readability and enhance their accuracy inside the examination. Given its significance in aggressive checks, this topic gives a very good balance of principle and numericals, making it important for securing better rankings.
Importance in NEET Exam
Understanding electrochemistry is important for NEET (National Eligibility cum Entrance Test) guidance for several motives:
- Core concept in chemistry: Electrochemistry is a essential topic in chemistry and is crucial for expertise redox reactions and their programs.
- Applications in diverse fields: Electrochemistry has programs in diverse fields, together with strength garage, corrosion prevention, and electroplating.
- Medical programs: Electrochemistry is utilized in scientific gadgets including pacemakers and defibrillators.
- NEET syllabus: Electrochemistry is a sizeable part of the NEET chemistry syllabus and can convey a good sized weightage inside the exam.
Download: Electrochemistry
| Title | Download |
|---|---|
| Electrochemistry NEET Questions with Answer |
Electrolytic Cells: Electrochemistry
Electrolytic Cells
Electrolytic cells are gadgets that use electric power to power non-spontaneous chemical reactions. In these cells, an immediate modern is exceeded through an electrolyte answer containing ions of the preferred substance, causing the ions to be reduced or oxidized on the electrodes.
Working Principle
- Electrolyte: The electrolyte solution includes ions of the substance to be electrolyzed.
- Electrodes: Electrodes (anode and cathode) are immersed inside the electrolyte answer.
- Direct modern-day: A direct cutting-edge is carried out to the electrodes, inflicting electrons to waft from the cathode to the anode.
- Redox reactions: At the anode, oxidation occurs, and ions lose electrons. At the cathode, discount takes place, and ions advantage electrons.
- Product formation: The merchandise of the redox reactions are fashioned at the electrodes.
Faraday’s Laws of Electrolysis
Michael Faraday formulated legal guidelines that govern the technique of electrolysis:
- Faraday’s First Law: The mass of a substance deposited or liberated at an electrode is at once proportional to the quantity of strength passed through the answer.
- Faraday’s Second Law: The loads of various materials deposited or liberated by means of the same amount of power are proportional to their equivalent weights.
Equivalent weight is the mass of a substance that reacts with or displaces 1 gram of hydrogen or eight grams of oxygen.
Applications of Electrolytic Cells:
- Electroplating: Coating metals with a skinny layer of another steel for safety or decorative purposes.
- Extraction of metals: Extraction of metals from their ores, which include aluminum and sodium.
- Purification of metals: Refining impure metals to reap pure forms.
- Production of chemicals: Production of chemicals which includes chlorine, sodium hydroxide, and hydrogen peroxide.
Galvanic (Voltaic) Cells: Electrochemistry
| Feature | Explanation |
|---|---|
| Working Principle | Galvanic cells convert chemical energy into electrical energy through spontaneous redox reactions. The two half-cells of the cell are connected by a salt bridge or porous barrier to allow the flow of ions. Electrons flow from the anode (negative electrode) to the cathode (positive electrode), generating an electric current. |
| Standard Electrode Potentials | The standard electrode potential (E°) of a half-cell is the potential difference between the electrode and a standard hydrogen electrode (SHE) under standard conditions. It is a measure of the tendency of an electrode to lose or gain electrons. Higher E° values indicate a greater tendency to gain electrons (reduction), while lower E° values indicate a greater tendency to lose electrons (oxidation). |
| Cell Potential (Ecell) | The overall potential of a galvanic cell is determined by the difference in standard electrode potentials of the two half-cells. Ecell = E°cathode – E°anode. A positive Ecell value indicates a spontaneous reaction. |
| Nernst Equation | The Nernst equation relates the cell potential to the concentrations of the reactants and products. It is used to calculate the cell potential under non-standard conditions. |
| Applications | Galvanic cells are used in batteries, fuel cells, and corrosion prevention. |
Nernst Equation: Electrochemistry
The Nernst Equation
The Nernst Equation is a fundamental equation in electrochemistry that relates the equilibrium ability of a half-reaction to the standard electrode ability, temperature, and the sports of the chemical species involved. It is derived from the Gibbs free energy equation and the relationship between the Gibbs free energy and the cell potential.
Derivation:
The Nernst Equation is derived from the Gibbs free energy equation:
ΔG = ΔG° + RT ln Q
where:
- ΔG is the change in Gibbs free energy for the reaction
- ΔG° is the standard change in Gibbs free energy for the reaction
- R is the gas constant
- T is the temperature in Kelvin
- Q is the reaction quotient
For a redox reaction, the change in Gibbs free energy is related to the cell potential (E) by the equation:
ΔG = -nFE
where:
- n is the number of electrons transferred in the reaction
- F is the Faraday constant
Substituting these equations into the Gibbs free energy equation, we get:
-nFE = -nFE° + RT ln Q
Rearranging and solving for E, we obtain the Nernst Equation:
E = E° - (RT/nF) ln Q
Applications:
The Nernst Equation has several applications in electrochemistry, including:
- Calculating equilibrium potentials: The Nernst Equation can be used to calculate the equilibrium potential of a half-reaction under non-standard conditions.
- Predicting cell potentials: The Nernst Equation can be used to predict the cell potential of a galvanic cell under different conditions.
- Determining concentrations: The Nernst Equation can be used to determine the concentration of a species in a solution from the measured cell potential.
- Studying corrosion: The Nernst Equation can be used to study corrosion processes, as corrosion is an electrochemical phenomenon.
Effect on Cell Potential:
The Nernst Equation shows that the cell potential (E) depends on the reaction quotient (Q). As the reaction proceeds, the concentrations of the reactants and products change, and thus the reaction quotient also changes. This affects the cell potential:
- If Q < 1: The reaction is not at equilibrium, and the cell potential is positive. This means that the reaction is spontaneous and proceeds in the forward direction.
- If Q = 1: The reaction is at equilibrium, and the cell potential is zero. This means that there is no net reaction occurring.
- If Q > 1: The reaction is not at equilibrium, and the cell potential is negative. This means that the reaction is non-spontaneous and proceeds in the reverse direction.
Electrode Potential and Electrochemical Series
Electrode Potential:
The ability difference developed between an electrode and the electrolyte answer wherein it is immersed. It is a measure of the tendency of an electrode to gain or lose electrons.
Standard Electrode Potential (E°): The electrode potential measured below popular situations (1 M awareness, 298 K, 1 atm strain).
Electrochemical Series:
A desk list the usual electrode potentials of numerous half of-reactions arranged so as in their reducing decreasing strength.
Elements at the pinnacle of the series have a strong tendency to advantage electrons (sturdy oxidizing marketers). Elements at the lowest of the collection have a sturdy tendency to lose electrons (robust decreasing agents).
| Element | Half-Reaction | Standard Electrode Potential (E°) (V) |
|---|---|---|
| Li | Li+ + e– → Li | -3.05 |
| K | K+ + e– → K | -2.93 |
| Ba | Ba2+ + 2e– → Ba | -2.90 |
| Ca | Ca2+ + 2e– → Ca | -2.87 |
| Na | Na+ + e– → Na | -2.71 |
| Mg | Mg2+ + 2e– → Mg | -2.37 |
| Al | Al3+ + 3e– → Al | -1.66 |
| Zn | Zn2+ + 2e– → Zn | -0.76 |
| Fe | Fe2+ + 2e– → Fe | -0.44 |
| Ni | Ni2+ + 2e– → Ni | -0.25 |
| Sn | Sn2+ + 2e– → Sn | -0.14 |
| Pb | Pb2+ + 2e– → Pb | -0.13 |
| H2 | 2H+ + 2e– → H2 | 0.00 |
| Cu | Cu2+ + 2e– → Cu | +0.34 |
| Ag | Ag+ + e– → Ag | +0.80 |
| Au | Au3+ + 3e– → Au | +1.50 |
Key Points:
- A fantastic E° cost suggests an inclination to gain electrons (oxidation).
- A negative E° fee suggests an inclination to lose electrons (reduction).
- A greater tremendous E° value manner a more potent oxidizing agent.
- A extra bad E° cost way a more potent reducing agent.
- The difference in E° values between half of-reactions can be used to predict the spontaneity of a redox response.
Applications of Electrochemical Series:
- Predicting the feasibility of redox reactions.
- Determining the strength of oxidizing and reducing dealers.
- Designing electrochemical cells (batteries, fuel cells).
- Corrosion prevention.
- Electroplating.
Conductance and Molar Conductivity
Conductance:
The capacity of a strategy to conduct electric cutting-edge. It is the reciprocal of resistance (G = 1/R).
Unit: Siemens (S)
Molar Conductivity:
The conductance of an answer containing one mole of the electrolyte. It is calculated by dividing the specific conductance (κ) with the aid of the molar concentration (c).
Unit: S m² mol⁻¹
Kohlrausch’s Law:
The molar conductivity at countless dilution (Λ°) of an electrolyte is the sum of the molar conductivities of its character ions.
Λ° = λ⁺ λ⁻
Where:
- Λ° is the molar conductivity at endless dilution
- λ⁺ is the molar conductivity of the cation
- λ⁻ is the molar conductivity of the anion
| Term | Definition | Unit |
|---|---|---|
| Conductance (G) | Ability of a solution to conduct electric current | Siemens (S) |
| Specific Conductance (κ) | Conductance of a unit volume of solution | S m⁻¹ |
| Molar Conductivity (Λ) | Conductance of a solution containing one mole of electrolyte | S m² mol⁻¹ |
| Molar Conductivity at Infinite Dilution (Λ°) | Molar conductivity when the concentration approaches zero | S m² mol⁻¹ |
| Kohlrausch’s Law | The molar conductivity at infinite dilution is the sum of the molar conductivities of its individual ions | – |
Electrochemical Cells and Gibbs Free Energy
| Parameter | Symbol | Equation | Interpretation |
|---|---|---|---|
| Gibbs Free Energy | ΔG | ΔG = -nFE | Measures the maximum work a system can do at constant temperature and pressure. |
| Faraday’s Constant | F | F = 96,485 C/mol | The amount of charge carried by one mole of electrons. |
| Number of Moles of Electrons | n | – | The number of electrons transferred in the redox reaction. |
| Electromotive Force (EMF) | E | E = -ΔG / nF | The potential difference between the electrodes of an electrochemical cell. |
Batteries and Fuel Cells: Electrochemistry
| Battery Type | Electrodes | Electrolyte | Applications | Advantages | Disadvantages |
|---|---|---|---|---|---|
| Lead-Acid | Lead anode, Lead(IV) oxide cathode | Sulfuric acid solution | Car batteries, emergency power supplies | Low cost, reliable, long cycle life | Heavy, environmental concerns (lead and acid), low energy density |
| Lithium-Ion | Lithium-ion intercalated carbon anode, metal oxide cathode (e.g., lithium cobalt oxide) | Lithium-ion salts in organic solvents | Laptops, smartphones, electric vehicles | High energy density, lightweight, long cycle life | Cost, safety concerns (fire risk), potential for capacity fade |
FAQs about Electrochemistry
1. What is electrochemistry?
Ans: Electrochemistry is the department of chemistry that studies the relationship between electric strength and chemical reactions, specially redox reactions.
2. What are the important subjects in electrochemistry for NEET?
Ans: Important topics include electrolysis, electrochemical cells, Nernst equation, conductance, Kohlrausch regulation, and Faraday’s laws of electrolysis.
3. What is an electrochemical cell?
Ans: An electrochemical cell is a device that generates electrical strength from a chemical reaction or uses electric energy to drive a chemical reaction.
4. What is the Nernst equation?
Ans: The Nernst equation calculates the electrode potential of a cell under non-standard conditions. It helps predict the voltage of electrochemical cells.
5. What are Faraday’s laws of electrolysis?
Ans: Faraday’s laws state that the amount of chemical change during electrolysis is proportional to the amount of electricity passed through the electrolyte.