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ELECTROCHEMISTRY | Complete Chapter in 1 Shot | Class 12th Board-NCERT

NCERT Wallah・82 minutes read

Electrochemistry is a crucial chapter for Class 12 Chemistry and NEET exams, covering topics like galvanic cells, electrolytic cells, and batteries. The conversion of electrical energy to chemical energy, electrode potential measurements, reduction potential, and electrolysis products are essential concepts discussed in the text.

Insights

  • Electrochemistry, a crucial topic for Class 12 Chemistry and NEET exams, involves the conversion of electrical energy to chemical energy through galvanic cells (spontaneous reactions) and electrolytic cells (non-spontaneous reactions), with the former generating electricity spontaneously and the latter requiring external current for electricity production.
  • Understanding electrode potential, reduction potential, and Faraday's Law is essential for determining products in electrolysis, with factors like concentration, conductance, and molar conductance playing key roles in the process, emphasizing the importance of these concepts in exam preparation and practical applications.

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Recent questions

  • What is Electrochemistry?

    Electrochemistry involves the conversion of electrical energy to chemical energy and vice versa. It encompasses galvanic cells, electrolytic cells, conductance in solutions, batteries, and corrosion.

  • How are galvanic cells and electrolytic cells different?

    Galvanic cells produce electricity spontaneously, while electrolytic cells require external current to produce electricity. Galvanic cells involve spontaneous reactions, while electrolytic cells involve non-spontaneous reactions.

  • What is the purpose of a salt bridge in a galvanic cell?

    A salt bridge is used to maintain neutrality in the solutions of a galvanic cell, ensuring continuous electron flow between the two half cells. It prevents the buildup of charge and allows the cell to function properly.

  • How is electrode potential measured in electrochemistry?

    Electrode potential is measured using a Standard Hydrogen Electrode under standard conditions at 25 degrees Celsius. The potential is considered zero for the Standard Hydrogen Electrode, and a voltmeter is used to measure the potential of the test electrode.

  • What determines the product in electrolysis?

    Reduction potential determines the product in electrolysis. For example, in the electrolysis of sodium chloride, Na+ is reduced at the cathode, and Cl- is oxidized at the anode. The product formed depends on the reduction potential of the elements involved.

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Summary

00:00

Essential Electrochemistry Concepts for Class 12

  • The chapter being discussed is Electrochemistry, crucial for Class 12 Chemistry and NEET exams.
  • The chapter covers galvanic cells, electrolytic cells, and conductance in solutions.
  • The chapter also delves into batteries and corrosion, all essential topics for exams.
  • Electrochemistry involves the conversion of electrical energy to chemical energy and vice versa.
  • Electrochemical cells consist of two electrodes in an electrolyte, generating electric current through chemical reactions.
  • Electrochemical cells are classified into galvanic cells (spontaneous reactions) and electrolytic cells (non-spontaneous reactions).
  • Galvanic cells produce electricity spontaneously, while electrolytic cells require external current to produce electricity.
  • In a galvanic cell, zinc and copper electrodes are placed in electrolytes to generate current flow.
  • The flow of electrons in the cell leads to oxidation and reduction reactions, producing current.
  • A salt bridge is used to maintain neutrality in the solutions of the galvanic cell, ensuring continuous electron flow.

19:46

"Daniel Cell: Oxidation, Reduction, and Electrode Potential"

  • Left half cell indicates oxidation is occurring, with a negative electrode.
  • Right half cell involves reduction.
  • Combination of reactions involves zinc solid and copper solid.
  • Resulting cell is named Daniel Cell, comprising zinc and copper.
  • Salt bridge maintains electrical neutrality in half cells.
  • Absence of salt bridge disrupts continuous electron flow.
  • Electrode potential is generated due to charge separation.
  • Standard conditions for potential measurement include 25 degrees Celsius.
  • Measurement of electrode potential involves a Standard Hydrogen Electrode.
  • Potential is considered zero for Standard Hydrogen Electrode.

45:44

Understanding Reduction and Oxidation Potential in Electrochemistry

  • Place a voltmeter in the middle to measure the potential directly across the test electrode.
  • The reading obtained indicates the potential of the test electrode.
  • Reduction potential should be indicated with a negative sign.
  • Understand oxidation potential through examples, like zinc with a reduction potential of 76 volts.
  • Elements in the electrochemical series are arranged in increasing order of standard reduction potential.
  • The reduction potential of elements below hydrogen is positive, indicating a tendency to be reduced.
  • The elements above hydrogen have negative reduction potential, showing a tendency to oxidize.
  • The strongest oxidizing agent is fluorine, with a reduction potential of 2.87 volts.
  • The reducing power of elements can be arranged in decreasing order based on their reduction potential.
  • Calculate the cell potential by summing the reduction potential of the anode and cathode in a cell.

01:20:14

"Electrochemistry: Copper, Charge, and Potential"

  • Concentration of copper needs to be divided by 10 Tu Di Power-4
  • Approximately make notes if value is known
  • The question asked in CBSE is important, solve it at home
  • Concentration of Nikhil and copper will determine the cell's potential
  • Thermodynamics of Galvanic Cell involves equilibriam constant and work done
  • Electrical work formula involves charge and potential
  • Charge on 1 mole of electrons is 96500 coulombs
  • Delta G formula involves electrical work
  • Reduction potential determines the product in electrolysis
  • Sodium chloride electrolysis results in Na+ reduction at cathode and Cl- oxidation at anode

01:54:46

Chemical Reactions and Product Formation in Electrolysis

  • Lena 4h plus Oxygen gas is the van off product
  • Hydrogen gas is a very important product in dilute Van of D with sulfuric acid
  • Electrolysis obtains the product of electrodiniach
  • Reduction of water in a solution of silver nitrate produces 4 h plus Oxygen gas
  • Sodium sulphate in water breaks down into Na+, sulphate, and water
  • The amount of product is directly proportional to the charge passed
  • Faraday's Law states that the mass of the product is directly proportional to the charge
  • The N factor in a balanced chemical reaction involves the number of electrons
  • The number of equivalents of all products is determined by the number of balance
  • Conductance is the reciprocal of specific resistance, also known as conductivity

02:28:04

Electrolytic Conductance: Papa's Om Inverse Unit

  • Conductance in solution is measured in centimeters, with Papa's unit becoming Om Inverse.
  • Understanding electrolytic conductance involves the formation of ions in a solution, leading to increased conductivity.
  • Electrolytic conductance depends on the nature of the electrolyte, the size of ions produced, and the nature of the solvent.
  • The concentration of the electrolyte affects conductance, with dilution increasing the volume and movement of ions.
  • Molar conductance is crucial in understanding electrolyte solutions, with the formula involving molarity and conductivity.
  • Papa's unit for molarity is centimeter inverse, with molar conductance being a key factor in conductivity calculations.
  • The Last Law of dilution is valid only at infinite dilution and zero concentration, ensuring complete dissociation of ions.
  • Conductivity of a salt solution is the sum of contributions from all ions present, leading to the overall conductivity.
  • Different types of batteries, such as primary and rechargeable ones like lead storage batteries, play essential roles in various devices.
  • Dry cells and mercury cells are examples of primary batteries, while lead storage batteries and fuel cells are rechargeable options.

02:59:44

Battery Chemistry in Low Current Devices

  • Graphite cathode is installed in dry cell, containing dry substances and an electrolyte paste of NH4Cl. The cell is suitable for low current devices and the representation of a Mercury cell is discussed.
  • Inverter batteries contain six cells connected, generating a total potential of 12 volts. The battery contains acid, typically a 38% solution of H2SO4, and reactions involving reduction of O2 and balancing of electrons are explained.
  • Discharge and charging reactions in LED storage batteries are discussed, with a focus on the reverse reactions occurring during charging. The importance of understanding these reactions in CBSE exams is highlighted.
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