Grade 10
  1. Matter and its properties  1.1. States of matter  1.2. Physical and chemical properties of matter  1.3. Classification of substances (elements, compounds, mixtures)  1.4. Changes in Matter (Physical and Chemical Changes)  1.5. Law of conservation of mass and law of definite proportions
  2. Atomic Structure  2.1. Historical development of the atomic model  2.2. Subatomic particles (protons, neutrons, electrons)  2.3. Atomic number, mass number and isotopes  2.4. Electronic Configuration and Energy Levels  2.5. Valency, ion formation and oxidation state
  3. Periodic table  3.1. History and Development of the Periodic Table  3.2. Modern Periodic Law and Periodic Trends  3.3. Groups and Periods in the Periodic Table  3.4. Trends in the Periodic Table  3.5. Metals, non-metals, metalloids and their properties  3.6. Noble gases and their chemical inertness
  4. Chemical bond  4.1. Formation of Chemical Bonds (Octet Rule)  4.2. Ionic Bonding and Properties of Ionic Compounds  4.3. Covalent Bond and Properties of Covalent Compounds  4.4. Metallic bond and its properties  4.5. Molecular geometry and VSEPR theory  4.6. Polarity and dipole moment of molecules  4.7. Intermolecular forces
  5. Chemical Reactions and Equations  5.1. Types of Chemical Reactions  5.2. Writing and balancing chemical equations  5.3. Law of conservation of mass in chemical reactions  5.4. Factors Affecting Chemical Reactions  5.5. Catalysts and their role in chemical reactions  5.6. Exothermic and Endothermic Reactions
  6. Stoichiometry and Chemical Calculations  6.1. Mole concept and Avogadro number  6.2. Molar Mass and Gram-Mole Conversions  6.3. Empirical and molecular formula  6.4. Stoichiometric calculations and chemical yield  6.5. Limiting and Excess Reactants
  7. Acids, Bases and Salts  7.1. Properties and Definitions of Acids and Bases (Arrhenius, Bronsted-Lowry, Lewis)  7.2. pH Scale, pOH, and Indicators  7.3. Neutralization reactions and salt formation  7.4. Strength of Acids and Bases (Strong vs. Weak Acids and Bases)  7.5. Common Acids and Bases in Daily Life  7.6. Salts, their solubility and applications
  8. Metals and Nonmetals  8.1. Physical and chemical properties of metals  8.2. Physical and Chemical Properties of Non-Metals  8.3. Reactivity Series of Metals and Displacement Reactions  8.4. Extraction of metals from ores  8.5. Corrosion, its causes and prevention  8.6. Alloys, their composition and uses
  9. Carbon and its compounds  9.1. Allotropes of Carbon  9.2. Hydrocarbons and their classification (alkanes, alkenes, alkynes)  9.3. Functional groups in organic compounds  9.4. Nomenclature of organic compounds (IUPAC system)  9.5. Isomerism in organic chemistry (structural and geometrical)  9.6. Important organic reactions (combustion, addition, substitution, polymerization)  9.7. Applications of organic compounds in industry and daily life
  10. Environmental Chemistry  10.1. Air Pollution (Sources, Effects and Control)  10.2. Water Pollution (Causes, Effects and Remedies)  10.3. Greenhouse effect and global warming  10.4. Ozone layer depletion and its effects  10.5. Green Chemistry and Its Applications  10.6. sustainable chemistry practice
  11. Thermochemistry  11.1. Heat and Energy Changes in Chemical Reactions  11.2. Exothermic and Endothermic Reactions  11.3. Enthalpy, enthalpy change, and heat of reaction  11.4. Specific heat capacity and calorimetry  11.5. Energy Changes in Combustion Reactions
  12. Electrochemistry  12.1. Electrolytes and non-electrolytes  12.2. Electrolysis and its applications (electroplating, extraction of metals)  12.3. Redox reactions (oxidation and reduction)  12.4. Galvanic cell and electrochemical series  12.5. Corrosion and electrochemical prevention methods
  13. Chemical kinetics and equilibrium  13.1. Rate of chemical reactions and its measurement  13.2. Factors affecting the reaction rate (catalyst, temperature, concentration)  13.3. Reversible and irreversible reactions  13.4. Dynamic equilibrium and equilibrium constant  13.5. Le Chatelier's principle and its applications
  14. Gases and Gas Laws  14.1. Properties of gases and kinetic molecular theory  14.2. Boyle's Law (Pressure-Volume Relation)  14.3. Charles's Law  14.4. Gay-Lussac's Law  14.5. Combined Gas Law and Ideal Gas Law  14.6. Real Gases vs Ideal Gases
  15. Nuclear Chemistry  15.1. Introduction to Radioactivity and Nuclear Reactions  15.2. Types of radioactive decay (alpha, beta, gamma)  15.3. Half-life and applications of radioactive isotopes  15.4. Nuclear fission and fusion reactions  15.5. Nuclear power generation and its environmental impact

Grade 10 → Electrochemistry ↓


Electrolysis and its applications (electroplating, extraction of metals)


Electrolysis is a chemical process in which electricity is used to break down compounds into their constituent elements or to deposit a substance on an electrode. It is a powerful technique used in a variety of applications such as electroplating and the extraction of metals.

Understanding electrolysis

To understand electrolysis, we must first understand the basic arrangement of an electrolytic cell. An electrolytic cell has two electrodes, an anode and a cathode, immersed in an electrolytic solution called an electrolyte. This solution must contain free ions that can move to conduct electricity.

Cathode (-) <------------------------------------[Electrolyte]-----------------------------------> Anode (+)

The electrolyte can be a liquid or a molten salt, and it must conduct electricity. A power supply connected to the electrodes causes a direct current to flow through the circuit, causing the electrochemical reactions to occur.

How electrolysis works

When electricity is passed through an electrolyte, chemical reactions occur on the surfaces of the electrodes:

  • The anode is where oxidation occurs. Here, electrons are lost by the ions or atoms. For example, in the electrolysis of water, oxygen gas is formed at the anode.
  • The cathode is where reduction occurs. Here, electrons are gained by the ions. Continuing the water example, hydrogen gas is produced at the cathode.

Consider the electrolysis of water where water (H 2 O) is split into hydrogen (H 2) and oxygen (O 2):

At the cathode:
2 H 2 O(l) + 2e - → H 2 (g) + 2 OH - (aq)

At the anode:
2 H 2 O(l) → O 2 (g) + 4 H + (aq) + 4e -

Applications of electrolysis

1. Electroplating

Electroplating is a process in which a thin layer of metal is deposited on the surface of a conducting material using electrolysis. This technique is used in various industries for purposes such as corrosion resistance, improving appearance, reducing friction or increasing thickness.

The object to be plated is made the cathode, while the metal used for plating is often used as the anode. The electrolyte contains a salt of the metal used for plating.

For example, in silver plating:

At the cathode:
Ag + + e - → Ag

At the anode:
Ag → Ag + + e⁺

In this instance, the silver ions present in the electrolyte move toward the cathode and are deposited on the object, forming a thin silver layer.

2. Extraction of metals

Electrolysis is also important in the extraction of metals from their ores, especially for the more reactive metals, which are difficult to extract by conventional smelting methods.

This process often involves the electrolysis of molten salts of metal ores. The ore is broken down into its component metallic and nonmetallic elements.

An example of this is the extraction of aluminum from aluminum oxide (Al 2 O 3):

At the cathode:
Al 3+ + 3e - → Al

At the anode:
2 O 2- → O 2 + 4e -

Here, at the cathode, aluminium ions are reduced to form aluminium metal, while at the anode, oxygen ions are oxidised to form oxygen gas.

Factors affecting electrolysis

There are several factors that affect the efficiency and outcome of the electrolysis process:

  • Nature of the electrolyte: Different electrolytes conduct electricity to different degrees.
  • Nature of the electrodes: The materials of the electrodes can affect electrolysis due to their reactivity or inertness.
  • Concentration of ions: The concentration of ions in the electrolyte affects the rate of electrochemical reactions.
  • Applied voltage: Higher voltages may increase the rate of reaction, but may also pose a risk of unwanted side effects.
  • Temperature: Increasing temperature often increases the reaction rate, but can also increase energy consumption.

Benefits of electrolysis

Electrolysis is a widely used process because of its following advantages:

  • Purity: It produces pure metal, which is important for many industrial applications.
  • Ability to deposit on complex shapes: Electroplating can evenly coat complex surfaces.
  • Control: This allows precise control over the thickness of the deposition during the plating process.
  • Environment friendly: It provides clean production without smelting, which emits harmful gases.

Limitations of electrolysis

Despite its many applications, electrolysis has some limitations:

  • Energy consumption: This process can be energy-intensive, especially for highly reactive metals.
  • Cost: The equipment and maintenance for an electrolysis setup can be expensive.
  • Purity of electrolytes: Contamination of the electrolyte can cause impurities or unwanted substances to accumulate.

Conclusion

Electrolysis is vital in modern industries, helping us improve the materials we use every day. Whether it's making things shiny through electroplating or extracting precious metals for use in various products, electrolysis is an invaluable tool in chemistry. Understanding its principles allows us to harness its full potential in a variety of practical applications.


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Electrolytes and non-electrolytes
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Redox reactions (oxidation and reduction)

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Electrolysis and its applications (electroplating, extraction of metals)

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