Acid, Base and Salt - Unit 09 | Class 10 | Solutions to Questions and Balanced Chemical Equations

Unit-09 | Acid Base and Salt | Class-10

Overview: Acids are those inorganic substances that give hydrogen ions when dissolved in aqueous solution. Bases are the metallic oxides or hydroxides. Salts are those neutral substances formed by the partial or complete replacement of hydrogen of acids by the metals of bases.  Acids are sour to taste and Bases are bitter to taste. This is a solved question and answer exercise of class 10 from the acids, bases, and salts portion of the chemistry of science. 

This is a full solution of Acid Bases and Salts chapter of grade 10 students. These solutions will help you score better marks in your board examination. Questions in groups A, B, C, and D are worth 1, 2, 3, and 4 marks, respectively.

Questions are taken from Oasis - School Science - Grade 10.

Group A

1. Define acid with any two examples.

Answer: Acid are those chemical substances that give hydrogen ions when dissolved in aqueous solution. Any two examples of acids are: Hydrochloric Acid and Acetic Acid.

2. What is an inorganic acid? Give any two examples.

Answer: Acid which is obtained from minerals and doesn't contain hydrocarbons is called an inorganic acid. Any two examples of inorganic acids are: Hydrochloric Acid and Sulphuric Acid.

3. Define organic acids with any two examples.

Answer: Acid which is obtained from living organisms and has hydrocarbons is defined as organic acids. Any two examples of organic acids are: Acetic Acid and Formic Acid. 

4. Name the acid found in each of the given substances:

i) Juice of lemon: Citric Acid

ii) Vinegar: Acetic Acid

5. Mention any two physical properties of acids. 

Answer: Any two physical properties of acids are:

i) Acids are sour to taste.

ii) Acids are corrosive in nature and can cause several burns. 

6. Define base and give any two examples.

Answer: Metallic oxide or metallic hydroxide is defined as base. Any two examples of base are: Sodium Hydroxide and Sodium Oxide.

7. What is an alkali? Give any two examples.

Answer: Alkali is a base that gives hydroxyl (H-) ions when dissolved in aqueous solution.

Any two examples of alkali are: Sodium Hydroxide and Potassium Hydroxide.

8. Write any two physical properties of bases.

Answer: Any two physical properties of bases are:

i) Bases are slippery to touch and bitter to taste.

ii) Bases turn red litmus paper into blue, methyl orange into yellow and phenolphthalein into pink colour.

9. Name any two alkalis that react with skin.

Answer: Any two alkalis that react with skin are:

i) Sodium Hydroxide

ii) Potassium Hydroxide

10. What is a salt? Give any two examples.

Answer: A salt is a chemically neutral substance formed by either partial or complete displacement of hydrogen ions of acids by the metal or radical of a base. 

Any two examples of salt are: Sodium Chloride and Calcium Sulphate.

11. Write any two physical properties of salts.

Answer: Any two physical properties of salts are:

i) Salts maybe colorless, white in color or of any other color.

ii) Most salts are neutral, but some may be acidic or basic in nature.

12. Define basic salt with one example.

Answer: Basic salt is defined as the salt formed by the reaction between a weak acid and a strong base. One example of basic salt is Sodium Carbonate.

13. Define neutral salt with one example.

Answer: Neutral salt can be defined as the salt formed by the reaction between a strong acid and a strong base or a weak acid and a weak base. One example of neutral salt is Sodium Chloride.

14. Name the bases which are used for given activities.

i) To soften hard water: Calcium Hydroxide

ii) To make soap soft: Potassium Hydroxide

15. Name the bases which are used for given activities.

i) To make plastics and chemical fertilizers: Ammonium Hydroxide

ii) To make bleaching powder: Calcium Hydroxide

16. Name the bases which are used for given activities.

i) To purify sugar: Calcium Oxide

ii) To purify petroleum products: Sodium Hydroxide

Group B

1. What are strong acids and weak acids? Give any two examples of each.

Answer: Strong acids are those acids that produce high concentration of hydrogen ions (more than 30%) when dissolved in aqueous solution. Two examples are: Nitric Acid and Sulphuric Acid.

Weak acids are those acids that produce less concentration of hydrogen ions (less than 30%) when dissolved in aqueous solution. Two examples are: Acetic Acid and Critic Acid.

2. Why is sodium chloride salty in taste?

Answer: Sodium Chloride stimulates the taste buds of our tongue that detect the salty taste. Hence, sodium chloride is salty in taste. 

3. What types of salts are neutral? Explain with examples.

Answer: Salts formed by the reaction between strong acids and strong bases (eg: HCl + NaOH -> NaCl + water) or weak acids and weak bases (eg: 2HCl+ PbO -> PbCl₂ + H₂O) are neutral salts.

4. Write any two differences between acids and salts. 

Answer: Any two differences between acids and salts are give below:

Acids	Salts
Acids are those chemical substances that produce hydrogen ions when dissolved in aqueous solution.	Salts are those substances formed by the partial or complete displacement of hydrogen of acids by a metal.
Generally, acids are corrosive in nature.	Generally, salts are neutral substances.

5.  Write any two differences between alkali and base. 

Answer: Any two differences between alkali and base are given below:

Alkali	Base
Alkali are those bases that dissolve in aqueous solution to give hydroxyl ions.	Metallic oxides or hydroxides are called bases.
All alkali are base.	All base are not alkali.

6. Write any two differences between strong acid and weak acid. 

Answer: Any two differences between strong acid and weak acid are:

Strong Acid	Weak Acid
Strong acids are those acids that produce high concentration of hydrogen ions (more than 30%) when dissolved in aqueous solution.	Weak acids are those acids that produce less concentration of hydrogen ions (less than 30%) when dissolved in aqueous solution.
They have low pH value, comparitively.	They have high pH value, comparitively.

7. Write any two differences between concentrated acid and dilute acid. 

Answer: Any two differences between concentrated acid and dilute acid are:

Concentrated acid	Dilute acid
Acids containing more concentration of acid is called concentrated acid.	Acids containing less concentration of acids and more water is called dilute acid.
They give more hydrogen ions when dissolved in aqueous solution.	They give less hydrogen ions when dissolved in aqueous solution.

8. H₂SO₄ is called an acid, why?

Answer: H₂SO₄ is called an acid because it produces hydrogen ions when dissolved in water. 

9. All alkalis are bases but not all bases are alkali. Give reason. 

Answer: All alkalis are bases but not all bases are alkali because bases may or may not dissolve in water but alkali are only those bases that dissolve in water. 

10. Citric acid is called a weak acid, why?

Answer: Citric acid is called a weak acid because it it produces less concentration of hydrogen ions when dissolved in aqueous solution.

11. Sodium Hydroxide is a called a base but sodium chloride is called a salt, why?

Answer: Sodium hydroxide is a metallic hydroxide so, it is called a base. But, sodium chloride is a neutral substance so, it is called a salt.

12. Hydrochloric acid is kept in plastic or glass bottle. Give reason.

Answer: Hydrochloric acid is kept in plastic or glass bottle because it is extremely corrosive in nature and actively reacts with metallic containers to corrode them. Whereas, it does not react with plastic or glass bottles. 

13. Explain why water can be considered as an acid as well as a base.

Answer: Water has potential to give either hydrogen ions or hydroxyl ions when it takes part in chemical reaction. Since, it shows properties of both acids as well as bases, water can be considered as an acid as well as a base. 

Group C

1. What happens when an acid is reacted with metallic carbonate? Write with balanced chemical reaction. 

Answer: When an acid is reacted with metallic carbonate, it produces salt, water and carbon dioxide gas. This can be written as:

HCl + Na₂CO₃ --> 2NaCl + H₂O + CO₂

Here, HCl = Hydrochloric Acid (Acid)

Na₂CO₃ = Sodium Carbonate (Metallic carbonate)

NaCl = Sodium Chloride (Salt)

H₂O = Water 

CO2 = Carbon Dioxide (Gas)

2. Name the compounds which are formed due to the chemical reaction between Nitric Acid and Calcium bicarbonate. 

Answer:

We know, Nitric Acid = HNO₃

Calcium bicarbonate = NaHCO₃

Now,

NaHCO₃ + HNO₃ = NaNO₃ + H₂O + CO₂

So, Sodium nitrate, water and carbon dioxide gas are formed as a result of the reaction between Nitric Acid and Calcium bicarbonate. 

3. Name any three acids which are used in our daily life. Also, write an application of each.

Answer: Any three acids which are used in our daily life along with their uses are mentioned below:

1. Sulphuric Acid: It is used in car batteries, to make paint, dyes, drugs, etc. 
2. Acetic Acid: It is used for preserving and flavoring our food. 
3. Hydrochloric acid is used to remove dirt, stains, etc. 

4. Write any three uses of acids. 

Answer: Any three uses of acids are:

1. Nitric acid, is used to make fertilizers, and to clean ornaments by goldsmiths.
2. Carbonic acid is used in soft drinks and soda water. 
3. Citric acid is used in medicines and flavoring foods. 

5. Write any three uses of salts.

Answer: Any three uses of salts are:

1. Calcium Sulphate is used to pasted the fractured bones. 
2. Silver Bromide is used in photography.
3. Sodium chloride is used as a food preservative.

6. Give an application each of the given compounds:

a) Hydrochloric Acid: It is used in printing and tanning industries. 

b) Nitric Acid: It is used to make chemical fertilizers.

c) Carbonic Acid: It is used in soft drinks and soda water. 

d) Sodium Chloride: It is used in our food and as a preservative. 

e) Citric Acid: It is used as a source of Vitamin-C in medicines. 

f) Magnesium Hydroxide: It is used to reduce hyperacidity in the stomach.

g) Calcium Sulphate: It is used to plaster fractured bones. 

h) Sodium Hydroxide: It is used to make soaps, detergents, paper, etc.

i) Sulphuric Acid: It is used in car batteries. 

j) Copper Sulphate: It is used to make fungicides. 

k) Sodium Carbonate: It is used to make soaps, detergents, and glasses. 

l) Sodium Bicarbonate: It is used in baking powder.  

m) Carbolic Acid: It is used to kill germs. 

n) Quick lime: It is used to purify sugar and reduce hardness of water. 

o) Ferrous Sulphate: It is used as a medicine to treat anaemic patients .

p) Ammonium chlroide: It is used in dry cell as a electrolyte. 

q) Ammonium sulphate: It is used as a chemical fertilizer. 

r) Vinegar: It is used for preserving and flavoring foods. 

7. Write down the following chemical changes into balanced chemical equation.

a) Metal oxide + Acid ---> Metal Salt + Water

Solution:

Let, metal oxide be NaO

acid be HCl

We get,

2NaO + 2HCl  ---> NaCl₂ + H₂O 

b} Acid + Metal ---> Salt + Water

Solution:

Let, acid be HNO₃

metal be Ca

We get,

6HNO₃ + 2Ca ---> Ca(NO₃)₂ + H₂O

c) Alkali + Ammonium salt ---> Salt + Gas + Water

Solution:

Let, alkali be Sodium Hydroxide and Ammonium salt be Ammonium Sulphate:

We get,

2NaOH + (NH₄)₂SO₄ --> Na₂SO₄ + 2NH₃ + 2H₂O

d) Acid + Base ----> Salt + Water

Solution:

Let, acid be Hydrochloric acid and base be Sodium Hydroxide:

We get,

NaOH + HCl -> NaCl + H₂O

8. Write down any three examples of neutralization reaction applied in our daily life. 

Answer: Any three examples of neutralization reaction applied in our daily life are:

i) 2HCl + Mg(OH)₂ ---> MgCl₂ + 2H₂O [ This helps to reduce the hyperacidity in the stomach.]

ii) Farmers use Calcium Oxide (lime) to neutralize the acidiity of soil.

iii) Honeybees and ants inject formic acid into our body. It can be neutralized by using soap.

Group D

1. Write any two chemical properties of acids with balanced chemical equation.

Answer: Any two chemical properties of acids with balanced chemical equation are:

i) Acid reacts with base to give salt and water:

HCl + NaOH --> NaCl + H₂O

ii) Acid dissolves in water and give hydrogen ions:

HCl ⇌  H⁺ + Cl^- 

2. Write any two chemical properties of bases with balanced chemical equation.

Answer: Any two chemical properties of bases with balanced chemical equation are:

i) Base reacts with acid to give salt and water:

NaOH + HCl --> NaCl + H₂O

ii) Bases react with carbon dioxide and form corresponding carbonate and water:

2NaOH + CO₂ --> Na₂CO₃ + H₂O

3. What happens in the given conditions? Write with balanced chemical equation.

i) When a metal reacts with dilute Sulphuric Acid. 

Answer: Let, the metal be Sodium (Na):

2Na + H2SO₄ ---> Na₂SO₄ + H₂

Hence, when a metal reacts with dilute Sulphuric Acid, metallic sulphate and hydrogen gas are obtained. 

ii) When an alkali reacts with ammonium salt.

Answer: Let, the alkali be NaOH; and ammonium salt be Ammonium Chloride:

NaOH + NH₄Cl ---> NaCl + H₂O + NH₃

Hence, when an alkali reacts with ammonium salt; salt, water and ammonia gas are obtained. 

4. Write short note on 'different types of salt'.

Answer: Different Types or Salt:

Salts are of five types on the basis of their properties. They are: neutral salts, acid salts, base salts, acidic salts, basic salts and hydrated salts. Neutral salts, eg: NaCl, are those salts which are formed by the reaction between acids and bases of same nature (strong or weak). Acid salts, eg: NaHSO₄, are salts formed by partial displacement of hydrogen ions of an acid. Base salts, eg: Zn(OH)Cl, are salts formed by partial replacement of a base by an acidic radical. Acidic salts, eg: CuSO₄, are the salts formed by reaction of a strong acid and a weak base. Basic salts, eg: Na₂CO₃ are the salts formed by reaction of a weak acid and a strong base. Hydrated salts, eg: Na₂CO₃.10H₂O, are salts containing certain molecules of water. 

5. Write the following reactions into balanced formula.

i) Sodium Hydroxide + Hydrochloric acid -> Sodium chloride + Water

Answer:

NaOH + HCl -> NaCl + H₂O

ii) Magnesium oxide + Sulphuric Acid -> Magnesium Sulphate + Water

Answer:

MgO + H₂SO₄ -> MgSO₄ + H₂O

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CLASS 10 QUESTIONS AND ANSWERS FROM CHAPTER 09 - ACIDS, BASES AND SALTS | ACID BASE AND SALT WORKSHEET WITH SOLUTIONS | IMPORTANT CLASS 10 CHEMISTRY SOLUTIONS 

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