Definitions and MCQs of Ninth class chemistry (acids, bases and salts)

Chapter 9Acids, Bases and Salts

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Definitions

Chemistry Def. & MCQs Dr. Sajid Ali Talpur

1. Acid: -A compound having usually sour taste and capable of neutralizing alkalis and reddening blue litmus paper, containing hydrogen that can be replaced by a metal or any other electropositive atom to form salt, or containing an atom that can accept electrons from a base.

2. Base: - A base is a substance that can accept hydrogen ions or more generally, donates electrons pairs.

3. Salt: -the ionic substance that result from the neutralization of an acid with a base.

4. Ph: - A measure of the acidity or alkalinity of a solution, numerically equal to 7 for neutral solutions, increasing with increasing alkalinity and decreasing with increasing acidity.

5. Arrhenius Theory: It states that an acid can be defined as a substance that yields hydrogen ions when dissolved in water. A base can be defined as a substance which yields hydroxide ions when dissolved in water.

6. Bronsted Lowery Theory: It states that an acid is a substance having a tendency to donate one or more protons and a base is a substance having a tendency to accept protons.

7. Lewis Theory: It states that an acid is any species (molecule or ion) which can accept a


pair of electrons and a base is any species (molecule or ion) which can donate a pair of electrons.

8. Titration: -titration is the quantitative measurement of an analyte in solution by completely reaction with reagent solution.

Indicators: -color showing organic compounds. OR for acid-base titrations, organic compounds that exhibit different colors in solution of different acidities; used to determine the point at which the reaction between two solutes is complete.

9. Buffer: -any substance that prevents changes in pH is known as buffer.

10. Neutralization: -when the two substances (acid and base) having opposed properties are allowed to react, salt and water are produced. The reaction is known as neutralization.

Multiple Choice Questions:


1. Ascorbic acid is the other name of:a) Vitamin A b) Vitamin Bc) Vitamin C d) Vitamin D

2. all are the properties of acids except:a) sour in taste b) smooth in touchc) proton donor d) electrons acceptor

3. the common acid in stomach is:a) HCl b) H2SO4

c) HNO3 d) H3PO4

4. The consumption of …… is an index to the state of civilization and prosperity of a country:a) HCl b) H2SO4

c) HNO3 d) H3PO4

5. the important acid for making explosive materials and fertilizers is:a) HCl b) H2SO4

c) HNO3 d) H3PO4

6. the souring of milk produces.a) citric acid b) lactic acidc) acetic acid d) fumaric acid

7. lemon, oranges, grape fruits contain: a) citric acid b) lactic acid

c) acetic acid d) fumaric acid

8. all are the properties of bases except:a) bitter in taste


b) aqueous solution conducts electricityc) undergo neutralization with acids

d) turn litmus paper to red.

Q 9 – 14 Select from the terms below: a) Arrhenius Theory b) Bronsted –lowery c) Lewis concept d) N.O.T

9. Bases are proton acceptors.

10. acids are sour in taste

11. acids are H+ ions donor

12. bases turn litmus paper to blue

13. ammonia is base

14. bases are electron donors

15. all are weak acids except:a) sulphuric acid b ) acetic acidc) formic acid d) phosphoric acid

16. which one is the normal salt:a) NaCl b) NaHSO4

c) KHCO3 d) Mg(OH) Cl17. which one is not double salt:

a) potash alum b) chrome alumc) Mohor’s salt d) table salt

Q18 -22 Select from the terms below:


a) Sodium carbonate b) backing soda c) copper sulphate d) Epsom salt e) potash alum f) N.O.T

18. it is a common double salt

19. used as antiacid and fire extinguishers

20. used as germicide, insecticide and in paint and varnish industry

21. it is used in softening of water, glass industry and as cleaning agent

22. used as anticeptic and mouth wash

23. water is not:a) universal solvent b) liquidc) present in urine d) amphoteric moleculee) N.O.T

24. The number of moles of solute dissolved per liter of solution is:a) molarity b) molalityc) titration d) pH

25. negative logarithm of hydrogen ion concentration is:a) molarity b) molalityc) titration d) pH

26. it is important for an analytical chemista) molarity b) molality


c) titration d) pH

Q 27 – 32

Select from the terms belowa) 0 b) 5-7c) 7 d) 7.4e) 14

27. it is the neutral pH

28. the pH of water is :

29. it is the highly acidic Ph

30. the pH of urine is:

31. the pH of blood is

32. pH + p OH = ?

33. Methyl orange produce…. Color in acidic solutiona) red b) greenc) yellow d) pink

34. a solution whose molarity or strength is known is called standard solution:a) true b) false

35. low p H of blood causes diabetes, diarrhea, vomiting.a) true b) false


36. water and CO2 are produced as a result of neutralization:a) true b) false

Answer Key

1 C 2 B 3 A4 B 5 C 6 B7 A 8 D 9 B10 D 11 A 12 D13 B 14 C 15 A16 A 17 D 18 E19 B 20 C 21 A22 E 23 E 24 C25 C 26 A 27 B28 D 29 E 30 A31 D 32 C 33 A34 A 35 B 36 B


Definitions and MCQs of Ninth class chemistry (acids, bases and salts)

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