Class 10 Science Chapter 2 Acid base and salts (2023)

9. Pool

10. Physical properties of bases

11. Kind of bases

12. Chemical properties of bases

13. Common to all bases

14. Dilution of acid and base

15. Acid and base strength

16. pH

17. Says

18. Properties of Salts

19. Family of Sales

20. Types of Salts

21. Production of Sodium Chloride (NaCl)

22. Production of P.O.P (CaSo4 . 1/2 H2O)

23. Production of caustic soda

24. Manufacture of Bleach Powder

25. Making Viranjak Powder.

Indicators:Indicators are substances that show the acidic or basic character of the solution by changing color.
Indicator type:There are many types of indicators. Some common types of indicators are:

1. Natural indicators:Indicators obtained from natural sources are referred to as natural indicators. Litmus, turmeric, red cabbage, China rose etc. are some common natural indicators that are commonly used to show the acidic or basic character of substances.
Tornazo:Litmus is made from lichen. The litmus solution is purple in color. Litmus paper comes in two colors: blue and red.
An acid turns blue litmus paper red.
A base turns red litmus paper blue.

Red cabbage:Red cabbage juice is originally purple in color. Red cabbage juice turns reddish with acid and greenish with lye.

2. Odor indicator:Substances that change odor when mixed with an acid or base are called odor indicators. For example; onion, vanilla, etc.
Onion:Onion paste or juice loses its odor when added to the base. It does not change its smell with acid.
Vanilla:The vanilla smell goes away with the base, but its smell doesn't go away with the acid.
Odor indicators are used to ensure the participation of students with visual impairments in the laboratory.

3. Synthetic indicator:The indicators synthesized in the laboratory are called synthetic indicators. For example; phenolphthalein, methyl orange, etc.
Phenolphthalein is a colorless liquid. Remains colorless with acid but turns pink with base.
Methyl orange is originally orange in color. It turns red with acid and yellow with base.

acids:Acids taste sour, turn blue litmus red, and dissolve in water to release H⁺ions
Example: sulfuric acid (H₂SO₄), acetic acid (CH₃COOH), nitric acid (HNO₃) etc
Acid properties:

• Acid tastes sour.
• Turns red litmus blue.
• The acid solution conducts electricity.
• Solte h⁺Ions in aqueous solution.

Types of acids:Acids are divided into two types according to their occurrence, namely natural acids and mineral acids.
(i) Natural acids:Acids obtained from natural sources are referred to as natural acids or organic acids.
Examples:
formic acid (HCOOH)
acetic acid (CH₃COOH)
oxalic acid (C₂H₂Ö₄) etc

(ii) Mineral acids:As examples of mineral acids, acids produced from minerals are known; Inorganic acids, artificial acids or synthetic acids are also referred to as mineral acids.
Example:
hydrochloric acid (HCl)
sulfuric acid (H₂SO₄)
Nitric acid (HNO₃)
carbonic acid (H₂CO₃)
phosphoric acid (H₃AFTER₄) etc

Zn(s) + 2HCl(ac) ----> ZnCl2(ac) + H2(g)

2Na(s) + H2SO4(aq) ----> Na2SO4(aq) + H2(g)

Hydrogen gas test:The gas produced after the acid reacts with the metal can be tested by holding a lit candle nearby. If the gas burns intermittently, this confirms the evolution of hydrogen gas. Burning with a popping sound is the hallmark of hydrogen gas.

(ii) Reaction of acids with metal carbonate:Acids give off carbon dioxide and its salts along with water when reacting with metal carbonates.
metal carbonate + acid → salt + carbon dioxide + water
Examples:
Hydrochloric acid gives off carbon dioxide gas, sodium chloride along with water when reacting with sodium carbonate.

Na2CO3(ac)+2HCl(ac) ---> 2NaCl(ac)+CO2+ H20

Sulfuric acid gives calcium sulfate, carbon dioxide gas, calcium sulfate and water when it reacts with calcium carbonate.

CaCo3(s) + H2SO4(aq) --> CaSO4(aq) + H2O(l)

Nitric acid yields sodium nitrate, water, and carbon dioxide gas when it reacts with sodium carbonate.

2HNO3(aq) + Na2CO3(aq)--> NaNO3(aq) + H2O(g0 +CO2(l)

(iii) Reaction of acid with hydrogen carbonates (bicarbonates):When reacting with metallic bicarbonate, acids give off gaseous carbon dioxide, its salt and water.
acid + metallic bicarbonate → salt + carbon dioxide + water
Example:
Sulfuric acid gives sodium sulfate, carbon dioxide and water when it reacts with sodium bicarbonate.

2NaHCO3(aq) + H2So4(aq) --> NaCl(aq) + Co2(g) + H2o(l)

Carbon Dioxide Gas Evolution Test:Carbon dioxide makes lime water milky as it passes through. This is the typical test for carbon dioxide gas.
The gas produced when the acid reacts with metal carbonate or metal bicarbonate makes lime water milky. This shows that the gas is carbon dioxide. This happens due to the formation of a white precipitate of calcium carbonate.

Ca(oH)2(aq) + Co2(g) --> CaCo3(aq) + H2o(g)

CaCo3(s) + co2(g) + H2o(l) --> Ca(HCo3)2(aq)

However, when excess carbon dioxide passes through the lime water, the milky color of the lime water disappears. This happens through the formation of calcium hydrogen carbonate. Since calcium hydrogen carbonate is soluble in water, the milky color of the mixed solution disappears.

Common in acids:Acids produce hydrogen gas when they react with metal. This shows that all acids contain hydrogen. For example; Hydrochloric Acid (HCl), Sulfuric Acid (H₂SO₄), nitric acid (HNO₃), etc
When an acid dissolves in water, hydrogen dissociates. The dissociation of the hydrogen ion in aqueous solution is a property common to all acids. An acid behaves acidic due to the dissociation of the hydrogen ion in aqueous solution.
Examples:
Hydrochloric acid (HCl) supplies the hydrogen ion (H⁺) and the chloride ion (Cl^–) dissolved in water.
HCl(ac) ----> H+(ac) + Cl-(ac)

acetic acid (CH₃COOH) to pure acetate (CH3COO^–) and hydrogen ions (H⁺).

CH3COOH(aqueous)-----> CH3COO-(aqueous) + H+(aqueous)

acids

strong acids
An acid that is fully ionized in water and (H⁺) is called a strong acid.
Examples: hydrochloric acid (HCl), sulfuric acid (H₂SO₄), nitric acid (HNO₃)

weak acids
An acid that is partially ionized in water and therefore contains a small amount of hydrogen ions (H⁺) is called a weak acid.
Example: acetic acid (CH₃COOH), carbonic acid (H₂CO₃)

When a concentrated acid solution is diluted with a water mixture, the concentration of hydrogen ions (H⁺) the hydronium ion (H₃Ö^–) per unit volume decreases.

Swimming pool:The bases have a bitter, soapy taste, turn litmus red to blue, and provide hydroxide ions (OH^–) in aqueous solution.
Examples: Sodium hydroxide (caustic soda) - NaOH
Calciumhydroxid – Ca(OH)₂
Potassium hydroxide (caustic potash) - (KOH)

Basic properties:

• Have a bitter taste.
• touch soap.
• Makes red litmus blue.
• conduct current in solution.
• Release OH^–Ions in aqueous solution

Basic types:Bases can be divided into two types: water soluble and water insoluble.
Alkaline and alkaline earth hydroxides are water soluble. These are also referred to as lyes.
For example; Sodium hydroxide, magnesium hydroxide, calcium hydroxide, etc. Alkali is considered a strong base.

Chemical properties of the bases:
(i) Basic reaction with metals:When alkali (base) reacts with metal, salt and hydrogen gas are formed.
alkali + metal → salt + hydrogen
Examples: Sodium hydroxide generates hydrogen gas and sodium zincate when reacting with metallic zinc.

2NaoH(aq) + 2Al(s) + 2H2O ---> 2NaAlO2(aq) + 3H2(g)

(ii) Reaction of the base with nonmetal oxides:Nonmetal oxides are acidic in nature. For example; Carbon dioxide is a non-metallic oxide. When carbon dioxide dissolves in water, carbonic acid is formed.
So when a base reacts with a nonmetal oxide, the two neutralize each other, resulting in salt and water, respectively.
Base + nonmetal oxide → salt + water
(Nonmetal oxides are acidic in nature)
Examples:
Sodium hydroxide gives sodium carbonate and water when it reacts with carbon dioxide.

2NaoH(aq) + CO2(g) -----> Na2Co3 (aq) + H2O(l)

Ca(OH)2 (aq) + Co2 (g) ---> CaCo3(s) + H2O(l)

(iii) Neutralization Reaction:An acid neutralizes a base when they react with each other to form their respective salts and water.
acid + base → salt + water
Because the reaction between acid and base neutralizes each other, it is also known as a neutralization reaction.
Examples: Sodium chloride and water are formed when hydrochloric acid reacts with sodium hydroxide (a strong base).

2HCL(aq) + Ca(OH)2(aq) --> CaCL2(aq) + 2H2O(l)

(iv) Reaction of acid with metal oxides:Metal oxides are basic in nature. So when an acid reacts with a metal oxide, both are neutralized. This reaction produces the respective salt and water.

acid + metal oxide → salt + water
(metal oxides are basic in nature)
Examples:
Calcium is a metal, so calcium oxide is a basic metal oxide. When an acid such as hydrochloric acid reacts with calcium oxide, a neutralization reaction takes place and calcium chloride is formed along with water.

2Hcl (aq) + CaO(s) ---> CaCl2 + H2O (l)

Also, when sulfuric acid reacts with zinc oxide, zinc sulfate and water are formed.

Common to all bases:A base dissociates the hydroxide ion into water, which is responsible for the basic behavior of a compound.
Example: When sodium hydroxide dissolves in water, the hydroxide ion and sodium ion dissociate.

KOH(ac) ----------> K+(ac) + OH-(ac)

Thus, the base shows its basic character due to the dissociation of the hydroxide ion.

OH-(ac) + H+(ac)------> H2O(l)

Example: When sodium hydroxide (a base) reacts with hydrochloric acid, sodium hydroxide breaks down into sodium ions and hydroxide ions, and hydrochloric acid breaks down into hydrogen ions and chloride ions.
The hydrogen ion and hydroxide ion combine to form water while the sodium ion and chloride ion combine to form sodium chloride.

NaOH(aqueous) + HCl(aqueous) -----> Na+(aqueous) + cl-(aqueous) + H2O

Acid and base dilution:The concentration of hydrogen ions in an acid and of hydroxide ions in a base per unit volume shows the concentration of acid or base.

Mixing acid with water decreases the concentration of hydrogen ions per unit volume. Likewise, by adding base to water, the concentration of hydroxide ions per unit volume decreases. This process of adding an acid or base to water is called dilution, and the acid or base is called dilution.

Dilution of acid or base is exothermic. Therefore, the acid or the base always adds to the water, and the water never adds to the acid or the base. When water is added to a concentrated acid or alkali, a lot of heat is generated, which can cause the acid or alkali to spatter and cause serious damage because concentrated acids and alkalis are highly corrosive.

Universal indicator:Litmus paper, phenolphthalein, methyl orange, etc. can only determine the acidic or basic character of a solution, but the use of these indicators gives no indication of the strength of the acid or base. So, in order to obtain the strength, as well as the acidic and basic nature of a given solution, the universal indicator is used.

(i) pH in our digestive system:Diluted HCl (hydrochloric acid) helps digest food (protein) in our stomach. Excess acid in the stomach causes heartburn (indigestion). Antacids such as magnesium hydroxide [Mg(OH)₂], also known as milk of magnesia, and sodium bicarbonate (sodium bicarbonate) are used to neutralize excess acid.

(ii) Dental caries caused by acids:The bacteria present in our mouth convert sugars into acids. When the pH of the acid that forms in the mouth falls below 5.5, tooth decay begins. Excess acid should be removed by cleaning the teeth with a good quality toothpaste as this type of toothpaste is alkaline in nature.

(iii) Soil pH and Plant Growth:Most plants will grow healthily when the soil is at a certain pH level (near 7), which should be neither alkaline nor overly acidic. Therefore,

• Compound “X” is sodium hydroxide (NaOH).
• Compound “A” is zinc sulfate (ZnSO₄).
• Compound “B” is sodium chloride (NaCl).
• Compound “C” is sodium acetate (CH₃COONa)

Dice:Salts are the ionic compounds formed after the neutralization reaction between acid and base. Salts are electrically neutral. There are several salts, but sodium chloride is the most common among them. Sodium chloride is also known as table salt or table salt. Sodium chloride is used to improve the flavor of foods.

Salt Properties:

• Most salts are crystalline soils.
• The salts can be transparent or opaque.
• Most salts are water soluble.
• The salt solution conducts electricity even when molten.
• Salt can be salty, sour, sweet, bitter, and umami (salty).
• Neutral salts are odorless.
• The salts can be colorless or colored.

Salt family:Salts that share acid or base residues belong to the same family.
Example:
(i) Sodium chloride (NaCl) and calcium chloride (CaCl₂) belongs to the chloride family.
(ii) Calciumchlorid (CaCl₂) and calcium sulfate (CaSO₄) belongs to the calcium family.
(iii) Zinkchlorid (ZnCl₂) and zinc sulfate (ZnSO₄) belongs to the zinc family.

Neutral, acidic and basic salts:
(i) Neutralsalz:The salts generated by the reaction between a strong acid and a strong base are neutral in nature. The pH of these salts is equal to 7, i.e. neutral.
Example: sodium chloride, sodium sulfate. potassium chloride, etc.

Sodium Chloride (NaCl):It is formed after the reaction between hydrochloric acid (a strong acid) and sodium hydroxide (a strong base).
NaOH (ac) + HCl (ac) -----> NaCl (ac) + H2O (l)

2NaOH(ac) + H2SO4(ac) ----> Na2So4(ac) + 2H2O(l)

Potassium chloride (KCl):It is formed after the reaction between potassium hydroxide (a strong base) and hydrochloric acid (a strong acid).

KOH(ac) + HCl(ac) ----> KCl(ac) + H2O(l)

NH4OH(ac) + HCl(ac) ------> NH4Cl(ac) + H2O(l)

Ammonium sulfate is formed after the reaction between ammonium hydroxide (a weak base) and sulfuric acid (a strong acid).
2NH4OH(aqueous) + H2SO4(aqueous) ---> (NH4)2SO4 + 2H2O(l)

(iii) Basic salts:The salts formed after the reaction between a weak acid and a strong base are called basic salts. For example; Sodium Carbonate, Sodium Acetate, etc.
Sodium carbonate is formed after the reaction between sodium hydroxide (a strong base) and carbonic acid (a weak acid).

H2CO3(aqueous) + 2NaOH(aqueous) ----> Na2CO3(aqueous) + H2O(l)

Sodium acetate is formed after the reaction between a strong base, sodium hydroxide (a strong base) and acetic acid (a weak acid).
CH3COOH(aq) + NaOH(aq)----> CH3COONa(aq) + H2O(l)

Cause of the formation of acidic, basic and neutral salts:

• When a strong acid reacts with a weak base, the base cannot completely neutralize the acid. This forms an acid salt.
• When a strong base reacts with a weak acid, the acid cannot completely neutralize the base. This creates a basic salt.
• When an acid and base of equal strength react, they are completely neutralized. This creates a neutral salt.

pH value salt:

• Neutral salt: The pH of a neutral salt is almost 7.
• Acid Salt: The pH of an acid salt is below 7.
• Basic Salt: The pH of a basic salt is greater than 7.

Some important chemical compounds
1. Table salt (sodium chloride):Sodium chloride (NaCl) is also known as table or table salt. It is formed after the reaction between sodium hydroxide and hydrochloric acid. It's a neutral salt. The pH of sodium chloride is around 7. Sodium chloride is used to improve the flavor of foods. Sodium chloride is used in the manufacture of many chemicals.

Sodium chloride important chemical
Sodium Hydroxide (NaOH):Sodium hydroxide is a strong base. It is also known as caustic soda. It is obtained by electrolytic decomposition of a common salt solution (brine). During the electrolytic decomposition of brine (aqueous common salt solution), the brine decomposes into caustic soda. The by-products are chlorine at the anode and hydrogen gas at the cathode. This entire process is known as the chlor-alkali process.
2NaCl(ac) + 2H2O(l) ----> 2NaOH(ac) + Cl2(g) + H2(g)

Use of products after brine electrolysis:

• Hydrogen gas is used as fuel, margarine, in the production of ammonia for fertilizers, etc.
• Chlorine gas is used in water treatment, PVC manufacturing, disinfectants, CFC, pesticides. It is also used in the manufacture of bleach powders and hydrochloric acid.
• Sodium hydroxide is used to degrease metals, make paper, soap, detergents, synthetic fibers, bleach, etc.

2. Bleichpulver (CaOCl₂):Bleach powder is also known as chlorinated lime. It is a solid and yellowish white color. Bleach powder is easily recognized by the strong smell of chlorine.
When calcium hydroxide (slaked lime) reacts with chlorine, calcium oxychloride (bleaching powder) is produced and water is formed.

Ca(OH)2(aq) + Cl2(aq) ---> CaOCl2 + H2O(l)

The aqueous bleach powder solution is basic in nature. The term bleach means color removal. Bleach powder is often used as a bleaching agent. It works due to oxidation. The chlorine in the bleaching powder is responsible for the bleaching effect.

Use of Bleach Powder:

• The bleaching powder is used as drinking water disinfectant, moss remover, herbicide, etc.
• The bleaching powder is used for bleaching cotton in the textile industry, for bleaching pulp in the paper industry.
• Bleach powder is used as an oxidizing agent in many industries, such as the textile industry, the paper industry, etc.

3. Backpulver (NaHCO₃):Sodium bicarbonate is another important product that can be recovered from the by-products of the chlor-alkali process. The chemical name for sodium bicarbonate is sodium bicarbonate (NaHCO₃) or baking soda. Baking soda, baking soda, baking soda, sodium bicarbonate, baking soda or just baking soda etc are some other names for baking soda.

How to prepare: Baking soda is made by reacting brine with carbon dioxide and ammonia. This is known as the Solvay process.

NaCl + H2O + CO2 + NH3 ----> NH4Cl + NaHCO3

Calcium carbonate is used as a CO source in this process.₂and the resulting calcium oxide is used to recover ammonia from ammonium chloride.

Properties of Baking Soda:

• Baking soda is a white crystalline solid but appears as a fine powder.
• Sodium bicarbonate is naturally amphoteric.
• Sodium bicarbonate is sparingly soluble in water.
• Thermal decomposition of sodium bicarbonate (sodium bicarbonate).
• When baking soda is heated, it breaks down into sodium carbonate, carbon dioxide, and water.
  2NaHCO₃+ heat → then₂CO₃+CO₂+H₂Ö
• Sodium carbonate formed after the thermal decomposition of sodium bicarbonate decomposes to sodium oxide and carbon dioxide on further heating.
  Von₂CO₃→ that's all₂O + CO₂
  This reaction is known as the dehydration reaction.

Using Baking Soda:

• Baking soda is used to make baking soda, which is used in cooking because it creates carbon dioxide and makes the dough soft and fluffy.
• Baking soda is used as an antacid.
• Baking soda is used in toothpaste, which whitens teeth and is plaque free.
• Baking soda is used to clean silver jewelry.
• Because sodium bicarbonate produces carbon dioxide and sodium oxide when heated to high temperatures, it is used as a fire extinguisher.

Backpulver:Baking soda produces carbon dioxide when heated, so it is used in cooking to fluff the dough. Although baking soda also produces carbon dioxide when heated, it is not used for cooking because baking soda produces sodium carbonate along with carbon dioxide when heated. The resulting soda ash makes the taste bitter.

NaHCO3 + C4H6O6 -----> CO2 + H2O + Na2C4H6O6

When baking soda is heated, sodium bicarbonate (NaHCO₃) decomposes to CO₂and sodium carbonate (Na₂CO₃). CO₂makes fluffy bread and cakes. Tartaric acid helps eliminate the bitter taste due to the formation of Na₂CO₃.

4. Laundry Soda (Sodium Carbonate)
Preparation method:Sodium carbonate is produced by the thermal decomposition of sodium bicarbonate obtained by the Solvay process.
NaCl + CO2 + NH3 + H2O ---> NH4Cl + NaHCO3

NaCO3 + 10H2O ------> Na2CO3 . 10H2O

Because sodium carbonate contains 10 water molecules, it is known as sodium bicarbonate decahydrate.
Sodium carbonate is a crystalline solid and soluble in water, while most carbonates are insoluble in water.

Use of soda:

• It is mainly used in cleaning cloths in rural areas.
• In the manufacture of detergents and powder cakes.
• For the permanent elimination of water hardness.
• It is used in the glass and paper industries.

The crystal water:Many salts contain water molecules and are known as hydrated salts. The water molecule present in the salt is called the water of crystallization.
Examples:
Copper sulfate pentahydrate (CuSO₄0,5 Std₂O): The blue color of copper sulfate is due to the presence of 5 water molecules. When copper sulfate is heated, it loses water molecules and turns gray - white, which is known as anhydrous copper sulfate. After adding water, the anhydrous copper sulfate turns blue again.