Acids Bases and Salts for Class 10 Notes

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Class 10 science chapter 2 you will learn that Acids, Bases, and Salts are important chemical substances that play a virtual role in our everyday lives. Substances with a pH level lower than 7, known to be sour in taste, are acids. People commonly find them in items like vinegar, citrus fruits, and battery acid.

On the other hand, bases have a pH level greater than 7 and people know them to be bitter in taste. We can find them in items such as soap, baking soda, and antacids.

The hydrogen ions from the acid combine with the hydroxide ions from the base to create them. People commonly use salt as a preservative, in cooking, and as a cleaning agent.

We must understand the properties of acids, bases, and salts because we can easily find them in our environment and they can have both positive and negative effects.

Industrial processes emit pollutants that result in acid rain, which can damage plants, animals, and buildings. Additionally, our body’s metabolism requires certain acids, while we use specific bases to neutralize stomach acid.

Introduction to Acids, Bases, and Salts


  • Acids are substances that have a sour taste and can dissolve metals.
  • They turn blue litmus paper red.
  • Acids have a pH of less than 7 on the pH scale, indicating that they are acidic.
  • Some common acids include vinegar (acetic acid), lemon juice (citric acid), and stomach acid (hydrochloric acid).
  • Acids can be strong or weak, depending on how much they dissociate in water.
  • Acids can react with bases in a neutralization reaction, which results in the formation of salt and water.
  • Acids have many practical applications, including in the production of fertilizers, cleaning products, and medicines.


  • Bases are chemical compounds with a pH greater than 7.
  • They are also known as alkaline substances.
  • Bases can be identified by their bitter taste and slippery or soapy texture.
  • Examples of common bases include baking soda, ammonia, and bleach.
  • Bases can be found in many household products, including cleaning agents, soaps, and detergents.
  • Bases react with acids in a neutralization reaction, which results in the formation of salt and water.
  • Bases are important in many industrial and scientific applications, including agriculture, manufacturing, and medical research.


  • Salts are chemical compounds that are formed from an acid and a base through a neutralization reaction.
  • Salts are typically made up of a metal ion and a non-metal ion.
  • Common types of salts include table salt (sodium chloride), Epsom salt (magnesium sulfate), and baking soda (sodium bicarbonate).
  • Salts have many practical applications in our daily lives, including food preservation, water softening, and as a component in many household products.
  • Salts can have different physical properties depending on their composition. For example, some salts may be soluble in water, while others may not be.
  • The properties of salts can also be influenced by other factors such as temperature, pressure, and the presence of other chemicals.
  • Salts play an important role in many chemical reactions and processes, including in biological systems such as the human body.

Types of Acids

Acids are divided into two types in this event. Natural acids and Mineral acids.

Natural Acids:

Acids that are obtained from natural sources are called natural acids


Methanoic acid (HCOOH)
Acetic acid (CH3COOH)
Oxalic acid (C2H2O4)

Acetic acidVinegar
Ascorbic acidGuava, amla
Citric acidLemon, orange
Lactic acidSour milk, curd
Methanoic acidAnt sting, nettle sting

Mineral Acids:

Mineral acids are a type of acid that is derived from minerals. These acids are also referred to as manufactured or synthetic acids also known as mineral acids.


Hydrochloric acid (HCl)
Sulphuric acid (H2SO4)
Nitric acid (HNO3)
Carbonic acid (H2CO3)

Test For Hydrogen Gas:

When an acid reacts with metal, the resulting gas can be identified by bringing a lit candle close to it. If the gas ignites and produces a popping sound, it indicates the presence of hydrogen gas. The distinctive feature of hydrogen gas is that it burns with a popping sound.

  • The reaction of acids with metal carbonate: When acids react with metal carbonates, O produces water and carbon dioxide gas and related salts.

Metal carbonate + Acid → Salt + Carbon dioxide + Water

Example: When sodium carbonate reacts with hydrochloric acid, it produces carbon dioxide gas, water, and sodium chloride. This chemical reaction can be described in simpler terms as something that happens when two substances come together to create three new things.

Some Important Chemical Compounds
1. Common Salt (Sodium Chloride): Sodium chloride (NaCl) is another name for table salt or common salt. People produce it by combining sodium hydroxide and hydrochloric acid. Sodium chloride is neutral, with a pH level of approximately 7. People commonly add it to food to enhance its flavor and use it in the production of various chemical substances.

Important chemicals from sodium chloride

Sodium Hydroxide (NaOH): 

The electrolytic breakdown of a solution of sodium chloride or brine produces sodium hydroxide, commonly called caustic soda, which is a potent base. This process separates the brine into sodium hydroxide, which is the desired product, as well as chlorine and hydrogen gas as byproducts.

2NaCl(aq) + 2H2O(l) → 2NaOH(aq) + Cl2(g) + H2(g)

Bleaching Powder (CaOCl2):

We already know that electrolyzing sodium chloride solution (brine) produces chlorine gas which is used in the production of bleaching powder. To make bleaching powder, we react chlorine gas with dry slaked lime [Ca(OH)2]. The chemical formula of bleaching powder is CaOCl2, but its actual composition is more intricate.

Ca(OH)2 + Cl2 → CaOCl2 + H2O

Use of Bleaching Powder:

  • Bleaching powder is employed as a disinfectant to purify water, eliminate moss, eradicate weeds, and so on.
  • Bleaching powder finds its application in the textile industry for the purpose of bleaching cotton and in the paper industry for bleaching wood pulp.
  • Bleaching powder is utilized as an oxidizer in numerous industries, including the textile and paper industries.

Baking Soda (NaHCO3):

Baking soda is a valuable substance that can be made from leftovers from the chloralkali process. It is known by many names, such as sodium hydrogen carbonate (NaHCO3) and sodium bicarbonate, as well as bread soda, cooking soda, and bicarbonate of soda, all of which are known names for baking soda.

Use of Baking Soda:

  • To create a baking powder, a blend of baking soda (sodium hydrogen carbonate) and a gentle, edible acid like tartaric acid is used. When baking powder is heated or combined with water, a specific chemical reaction happens.
  • Sodium hydrogen carbonate is a component in antacids that helps to alleviate discomfort. It neutralizes excessive acid in the stomach due to its alkaline nature.

Importance of pH in our daily life

  • Plants and animals pH sensitive:-

The pH range of 7.0 to 7.8 is crucial for the functioning of our body, and living organisms can only tolerate a limited pH variation. Acid rain occurs when the pH of rainwater drops below 5.6. This acidic precipitation can lower the pH of river water, making it difficult for aquatic life to survive in such conditions.

  • pH in the digestive system

The pH in the digestive system plays a crucial role in the breakdown and absorption of nutrients. The stomach produces hydrochloric acid with a pH of around 1.5 to 3.5 to break down food, while the small intestine has a slightly alkaline pH of 7 to 8, which aids in nutrient absorption. Any imbalance in pH can lead to digestive issues and discomfort

  • pH of Soil

The pH of the soil is a measure of its acidity or alkalinity and ranges from 0 to 14. People consider a pH of 7 as neutral, while values below 7 indicate acidity and values above 7 indicate alkalinity.

Most plants grow best in slightly acidic soil with a pH range of 6.0 to 7.0. Soil pH affects nutrient availability and can impact plant growth and health.

  • pH in tooth decay

Tooth decay is greatly influenced by the pH balance in the human mouth. Acidity can begin to destroy tooth enamel when the pH falls below 5.5.

Bacteria can produce acids that lower the pH level of the mouth, increasing the risk of tooth decay.

Chemicals from Common Salt

Commonly referred to as table salt, sodium chloride is a ubiquitous salt with a molecular structure of NaCl. This compound is an important component of our diet and is often used as a flavoring and preservative in foods.

Additionally, common salt is a starting material for many important compounds such as sodium hydroxide, chlorine, hydrochloric acid, and sodium carbonate.

  1. Sodium hydroxide or lye or caustic soda
  2. Baking soda or sodium hydrogen carbonate
  3. Washing soda or sodium carbonate decahydrate
  4. Bleaching powder or calcium hypochlorite

Class 10 Science Notes

Chapter of class 10 science basically includes some important Chapter topics from the NCERT Book, Such as acids bases and salts, metals and non-metals, chemical reactions and equations, Carbon and its Compounds, Life Processes, Control, and Coordination, etc.

Chapter-wise notes on these subjects are available in the table below, click on the links to access them.


Q: What are some examples of common acids?

A: Some examples of common acids include hydrochloric acid (HCl), sulfuric acid (H2SO4), and acetic acid (CH3COOH).

Q: What are some examples of common bases?

A: Some examples of common bases include sodium hydroxide (NaOH), potassium hydroxide (KOH), and magnesium hydroxide (Mg(OH)2).

Q: What is the pH scale?

A: The pH scale is a scale that measures the acidity or basicity of a solution. The scale ranges from 0 to 14, with solutions having a pH of 7 considered neutral, solutions with a pH less than 7 considered acidic, and solutions with a pH greater than 7 considered basic.

Q: What is the difference between a strong base and a weak base?

A: A strong base completely dissociates in water, releasing all of its hydroxide ions, while a weak base only partially dissociates in water, releasing some of its hydroxide ions.

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