Unit 10: Acids, Bases and Salts

What are Acids, Bases, and Salts?

Acids, Bases, and Salts are fundamental concepts in Chemistry that explain the nature and behavior of various substances. This unit explores the properties of acids and bases, their reactions, and how they interact to form salts. Students will learn about the pH scale, which measures the acidity or alkalinity of a solution, and how neutralization reactions occur between acids and bases.

Key Topics in Acids, Bases, and Salts:

• Properties of Acids and Bases: Understanding the physical and chemical characteristics of acids and bases, including their taste, pH, and reaction with metals.
• The pH Scale: Learning how the pH scale is used to determine the strength of an acid or a base, and its significance in chemical reactions.
• Neutralization Reactions: Exploring the process in which acids and bases react to form water and salts, balancing pH levels.
• Types of Salts: Examining different types of salts, such as acidic, basic, and neutral salts, and their formation through various reactions.
• Applications in Daily Life: Studying the uses of acids, bases, and salts in everyday life, including their role in food, cleaning products, and industry.

Benefits of Studying Acids, Bases, and Salts:

• Practical Knowledge: Equips students with an understanding of chemical substances that are commonly encountered in daily life.
• Analytical Skills: Enhances the ability to analyze and predict the outcomes of acid-base reactions, essential for advanced Chemistry studies.
• Real-World Applications: Provides insights into the practical uses of acids, bases, and salts in various fields, from medicine to manufacturing.

This unit is vital for students to grasp the chemical properties and reactions of acids, bases, and salts, forming a foundation for more complex topics in Chemistry. Understanding these concepts is key to success in both academic and practical applications.

1. A base is a substance which neutralizes an acid,Which of these substances is not a base?

a. aqueous ammonia
b. sodium chloride
c. sodium carbonate
d. calcium oxide

2. Lewis acid-base concept have the following characteristics except

a. formation of an adduct
b. formation of a coordinate covalent bond
c. donation and acceptance of an electron pair
d. donation and acceptance of a proton

3. Acetic acid is used for

a. flavouring food
b. making explosive
c. etching designs
d. cleaning metals

4. A salt is not composed of

a. a metallic cation
b.non metallic anion
c. an anion of a base
d. an anion of an acid

5. If a liquid has a pH of 7 then it must

a. be a colorless and and odourless liquid
b. freeze at 0^oC and boils at 100^oC
c. be neutral
d. be a solution containing water

6. A salt always

a. contains ions
b. contains water of crystallization
c. dissolves in water
d. forms crystals which conduct electricity

7. Dilute acids react with carbonates to produce the given products except

a. salt
b. water
c. carbon dioxide
d. hydrogen

8. In the preparation of insoluble salts, which one of the facts is incorrect?

a. two soluble salts are mixed
b. two soluble salts are produced
c. one of the salt produced is insoluble
d. both of the salt produced are insoluble

9. A reaction between an acid and base produces

a. salt and water
b. salt and gas
c. salt and an acid
d. salt and a base

10. The conjugate acid of HPO4^2- is

a. PO₄^3-
b. H₂PO₄^2-
c. H₂PO₄^–
d. H₃PO₄

11. What is the pOH of a 0.02M Ca(OH)2 ??

a. 1.698
b. 1.397
c. 12.31
d. 12.61

12 Which one of the following species is not amphoteric

a. H2O
b. NH3
c. HCO3^–
d. SO4^2-

13. The product of lewis acid base reaction is called adduct. The bond between the adduct specie is

a. ionic
b. covalent
c. metallic
d. coordinate covalent

14. The water of crystallization is responsible for the

a. melting point of crystals
b. boiling point of crystals
c. shapes of crystals
d. transition point of crystals

15. You want to dry a gas , which one the following salts you will use

a. CaCl2
b. NaCl
c. CaO
d. Na2SiO3

16. Ferric hydroxide is precipitated out of solution when aqueous sodium hydroxide solution is added to ferric chloride FeCl3 + 3NaOH …….> Fe(OH)3 + 3NaCl Color of the precipitate is

a. white
b. blue
c. dirty green
d. brown

17. Which ion is the conjugate base of sulphuric acid

a. SO3^2-
b. S^2-
c. HSO3^–
d. HSO4^–

18. Which one of the following is a lewis base

a. NH3
b. BF3
c. H⁺
d. AlCl3

19. According to lewis concept , acid is a substance which can

a. donate a proton
b. acceot a proton
c. donate a pair of electron
d. accept a pair of electron

20. Given Kw = [H⁺][OH^–]= 1.0 *10^-14 at 25^oC . What is the concentration of H⁺ in pure water at 25⁰C ?

a. 1* 10^-7 moldm^-3
b. 1* 10⁷ moldm^-3
c. 1* 10^-14 moldm^-3
d. 1* 10¹⁴ moldm^-3