Acid, Base and Salt || Base and Salt

Base and Salt

Q1. Mention the uses of acids in our daily life.

Ans:

The uses of acids in our daily life are:

1. Mineral acids are used in the laboratories as reagents.
2. Sulphuric acid is used for manufacturing drugs and detergents.
3. Nitric acid is used in manufacturing of chemical fertilizers, explosive and plastics.
4. Hydrochloric acid is used for bleaching purpose in textile industries, for making glue etc.
5. Boric acid is used for washing eyes and wounds.
6. Carbonic acid is used to make soda water.
7. Acetic acid is used for flavour.
8. Ascorbic acid is used in the treatment of scurvy.

Q2. What are the uses of base in our daily life?

Ans:

The uses of base in our daily life are as follows:

1. Potassium hydroxide is used in washing clothes.
2. Sodium hydroxide is used for making soaps.
3. Aluminium hydroxide is used as medicine-antacid against gastric disease.

Q3. Define salt. How can we prepare it? Write some examples.

Ans:

Salt is a chemical substance which is formed by partial or complete replacement of hydrogen atom by a metal or ammonium radical. 

Salt is prepared by the combination of acid and base. For examples; Calcium chloride (CaCl₂), Copper Sulphate (CuSO₄), Sodium nitrate (NaNo₃), etc. 

Q4. Define normal salt and write example.

Ans:

A salt which is produced by the complete displacement of hydrogen atom from an acid by a metal is called normal salt. For example: Sodium Chloride (NaCl), Potassium Chloride (KCl), Sodium Sulphate (Na₂SO₄), etc. 

Q5. What do you mean by acidic salt? Mention some example.

Ans:

The salt which is obtained by the partial displacement of hydrogen atom of an acid by a metal is called acidic salt. For example: Ammonium acetate (NH₄Cl), Sodium bisulphate (NaHSO₄), etc. 

Q6. Define basic salt with examples.

Ans:

The salt which is obtained by the partial displacement of hydroxyl group of a base by an acid radical is called basic salt. For example: Sodium acetate (CH₃COONa), Potash alum or phitkiri [K₂SO₄Al₂(SO₄)₃,12H₂O], etc. 

Q7. What is meant by hydrolysis?

Ans:

A chemical reaction in which a compound reacts with water to form a new substances is called hydrolysis.

Q8. Give reason:

1. Orange and lemon have sour taste.
Ans:
Orange and lemon contain citric acid. So, they have sour taste.
2. Acids sgould be hadled with care.
Ans:
Strong acids (Laboratory acids) are corrosive and can burn our skin, tongue, etc. So, acids should be handled with care.
3. All alkalis are base but all bases are not alkalis.
Ans:
All metallic oxides and hydroxides are called bases. But only water soluble metallic oxides are called alkalis. So, all alkalis are bases but all bases are not alkalis.

Ans:

Properties of salts are:

1. Salts are usually neutral to the indicators.
2. Salts have high melting points and boiling points.
3. The solution of salt can conduct electricity.
4. Most of the salts are soluble in water.

Q10. Name any two salts which are insoluble in water.

Ans:

The salts of barium and lead are insoluble in water. For example: Barium chloride (BaCl₂) and lead sulphate (PbSO₄).

Q11. Write the uses of salts in our daily life.

Ans:

The following are the uses of salts in our daily life:

1. Sodium chloride is used in preparing food.
2. Copper sulphate is used in the form of insecticide.
3. Magnesium sulphate is used as medicine against constipation.
4. Calcium sulphate (gypsum) is used in the form of plaster to join the fractured bones.

Q12. What is an indicator? Write the names of any-3 indicators that are used in the laboratory.

Ans:

An indicator is a chemical substance which is used to identify whether an object is acidic or basic. For example: Litmus paper, Methyl orange, Phenolpthalein etc. are some indicators that are used in the laboratory. 

Q13. How are litmus paper made?

Ans:

Litmus is ectracted in the form of solution from plants such as lichen, red rose flower or beet root. A litmus paper is prepared by soaking filter paper in litmus solution and then drying.

Q14. Define universal indicator.

Ans:

The inbdicator which indentifies the acid, base and salt with their strength is called universal indicator for example P^H paper.

Q15. How is universal indicator made?

Ans:

Universal indicator is made by mixing the different coloured ordinary indicators.

Q16. How do chemicals identify with the help of colour change in indicator?

Ans:

If the indicator changes into red or dark red then the substance is acid, Similarly, if the indicator changes into blue and dark blue then the substance is base.

If the indicator becomes green then the substance is neutral.

Ans:

The following table shows how acid, base and salt affect indicators: 

Indicator	Acid	Base	Salt
Red Blue	Neutral	Turns into blue color	netural
Blue Litmus	turns into red colour	neutral	neutral
Phenolpthalein	colourless	turns into pink color	neutral
Methyl Orange	turns into red color	turns into yellow color	neutral