C4.1 Acids, Bases and Salts

1. Mention the metal hydroxide which forms a blue precipitate when sodium hydroxide is added onto its solution?

Iron (II) hydroxide

Zinc hydroxide

Aluminum hydroxide

Copper (II) hydroxide

2. Explain the reason why Sodium Hydroxide is a strong base than the Ammonia solution and what is its effect on electoral conductivity?

Sodium hydroxide solutions contain fewer hydroxide ions than ammonia solution

Sodium hydroxide solution contains many hydrogen ions than ammonia solution

The presence of many hydroxide ions in Sodium hydroxide solutions makes it to strongly conduct electricity than ammonia solution

Both B and C

3. When Ammonia gas dissolves in a non-polar solvent such as Methylbenzene what will occur?

No effect on the litmus paper

The ammonia molecule doesn’t dissociate at all

There is no presence of hydroxide ions in the solution

All of the above

4. Mention the disadvantages of hard water?

Wastes soap

Stains white clothes as the soap precipitates out calcium and magnesium ions as scum which forms stain on clothes

Deposition of fur (calcium carbonate) in kettles, pipes and boilers

All of the above

5. Mention the salts which its solubility remains constant with temperature?

Sodium Chloride

Calcium Sulphate

Calcium ethanoate

Both A and B

6. All Metal Chloride salts are soluble except Lead (II) ions which are insoluble but in warm water Lead (II) Chloride is soluble. True or False

FALSE

TRUE

Maybe

None

7. Sodium, Potassium and Ammonium carbonate salts are soluble the rest are all insoluble and form precipitates. True or False

FALSE

Maybe

TRUE

None

8. All metal Sulphates are soluble except Barium and Lead Sulphate which form precipitate. True or False

TRUE

FALSE

Maybe

None

9. An acid is a substance that dissociates in water to give hydrogen ions as the only positive charged ions. True or False

FALSE

Maybe

TRUE

None

10. Mention the metal hydroxide which forms a green precipitate when sodium hydroxide is added onto its solution?

Iron (II) hydroxide

Zinc hydroxide

Aluminum hydroxide

Iron (III) hydroxide

11. For most salts solubility increases with?

Decrease in temperature

Constant temperature

Increase in temperature

None of the mentioned

12. The higher the number of hydroxide ions the higher the pH value and the greater the conductivity in the base solution? True or False

FALSE

Maybe

TRUE

None of the mentioned

13. Water hardness that is removed by boiling is known as?

Permanent

Temporary

Contract

Casual

14. Metal oxides which react with both as acids and bases to form a colorless solution are known as?

Polar solvent

Deliquescent

Efflorescent

Amphoteric oxides

15. A molecule which behaves as if it is negatively charged in one end and positively charged in the opposite end is said to be?

Deliquescent

Efflorescent

Polar solvent

None of the mentioned

16. A salt is defined as an ionic compound formed when a cation derived from a base combines with an anion from an acid. True or False

FALSE

TRUE

Maybe

None

17. The separation of different salts by making use of the differences in solubility in the same solvent is known as

Solvay process

Fractional distillation

Fractional crystallization

None of the mentioned

18. Water which readily lathers with soap is called

Soft water

Distilled water

Hard water

None of the mentioned

19. Which of the following statement is CORRECT WHEN AN ACID REACTS WITH A BASE?

It forms salt and water

The hydrogen ions from the acid react with the hydroxide ions from the base to form water.NaOH (aq) + HCl (aq) = NaCl (aq) + H2O(l) hence

H+ (aq) + OH- = H2O (l)

All of the above

20. The hydroxides of Magnesium (Mg), Zinc (Zn), Aluminum (Al), Iron (II), Iron (III), Copper (Cu) and Lead (II) ions forms a precipitate. True or False

FALSE

Maybe

TRUE

None

21. Describe a strong acid in terms of the number of hydrogen ions present and pH value?

The higher the number of hydrogen ions the lower the pH value making the solution a strong acid

The fewer the number of hydrogen ions the higher the pH value making the solution a strong acid.

The fewer the number of hydrogen ions are the lower the pH value making the solution a strong acid

None of the mentioned.

22. Mention the benefits of complex ions?

Used in the industry for softening of hard water as used in ion exchangers

Used in the industry to the extraction of some metals such as aluminum ores

Chlorophyll and hemoglobin are complex ions

All of the above

23. A substance that dissociates in water o produce hydroxide as the only negatively charged ions are called?

Acids

Bases

Neutral

None of the mentioned

24. Water hardness that cannot be removed by boiling is called?

Permanent

Temporary

Contract

Casual

25. What occurs when hard water is boiled?

Calcium hydrogen carbonate is boiled and precipitates out as Calcium carbonate

Magnesium hydrogen carbonate is boiled and precipitates out as Magnesium carbonate

The resulting solutions form lather readily with soap.

All of the above

26. Mention the metal hydroxide which forms a white precipitate when sodium hydroxide is added onto its solution

Magnesium hydroxide and Lead (II) hydroxide

Zinc hydroxide

Aluminum hydroxide

All of the above

27. Describe the chemical equation when the hydroxides of Zinc, Aluminum and Lead hydroxide (which are precipitates) reacts with excess sodium hydroxide or potassium hydroxide to form soluble complex ions?

Zn(OH)2 (S) + 2OH (aq)- = [ Zn(OH)4]2- colorless

Al(OH)2(S) + OH-(aq) = [Al(OH)4] (aq) colorless

Pb(OH)2 (S) + 2OH-(Aq) = [Pb(OH)4]2- colorless

All of the above

28. All metal Sulphites are soluble except they react with dilute hydrochloric acid or nitric acid to produce Sulphur (IV) oxide gas. True or Fasle

TRUE

FALSE

Maybe

None

29. Which of the following statement describes a polar solvent

A molecule that behaves as if it is negatively charged in one end and positively charged in the opposite end.

Its negative atom in the molecule has a higher ability to attract electrons compared to its positive atom in the molecule e.g. Hydrogen Chloride gas

The solvent is acidic in nature due to the presence of Hydrogen ions.

All of the above

30. When Ammonia gas dissolves in a polar solvent such as water, what will occur?

It turns red litmus paper blue

Ammonia molecule dissociates and reacts with water to form Ammonium Hydroxide

There is the presence of Hydroxide ions

All of the above

31. Hydrochloric acid is a strong acid than Ethanoic acid, what does it mean?

Hydrochloric acid has a low pH value and ethanoic acid has a high pH value.

Hydrochloric acid has a higher number of hydrogen ions

Ethanoic acid has a lower number of hydrogen ions

All of the above

32. When Hydrogen Chloride gas dissolves in a polar solvent such as water what will occur

It forms a solution that turns a blue litmus paper red.

The molecule dissociates in water

Presence of positively charged hydrogen ions and negatively charged chloride ions

All of the above

33. Which of the following is not an amphoteric oxide

Lead oxide

Zinc Oxide

Aluminum Oxide

Potassium Oxide

34. The hydroxides of Zinc, Aluminum and Lead hydroxide (which are precipitates) react with excess sodium hydroxide or potassium hydroxide to form soluble complex ions. True or False

TRUE

FALSE

Maybe

None

35. The hydroxides of Zinc and Copper (which are precipitates) react with excess Ammonia solution to form soluble complex ions. True or False

FALSE

Maybe

TRUE

None

36. When Hydrogen gas dissolves in a non-polar solvent such as Methylbenzene what will occur

No effect on dry litmus paper

The molecule does not dissociate at all.

There is no presence of hydrogen ions

All of the above

37. Mention the salts which its solubility decrease with temperature?

Sodium Chloride

Calcium Sulphate

Calcium ethanoate

None of the mentioned

38. Mention the metal hydroxide which forms a brown precipitate when sodium hydroxide is added onto its solution?

Iron (II) hydroxide

Zinc hydroxide

Aluminum hydroxide

Iron (III) hydroxide

39. What is the solubility of a solute in a solvent?

Is the minimum mass of solute required to saturate a solvent

Is the maximum mass of solute required to saturate a solvent

Is the maximum mass of solute required to saturate 100g of solvent at a particular temperature

None of the mentioned

40. Mention the advantages of hard water?

It provides calcium which is essential for strengthening bones

41. A precipitate is an insoluble solid that separates out from a solution during a chemical reaction. True or false

TRUE

FALSE

Maybe

None

42. Aqueous solutions which have a few hydrogen ions are known as?

Strong acids

Weak acids

Neutral solutions

All of the above

43. Which of the following is not an example of a polar solvent from the below list

Hydrogen chloride gas

Water molecule

Methylbenzene

None of the mentioned

44. Explain the reason why Hydrochloric acid has a stronger electrical conductivity than ethanoic acid

Presence of fewer hydrogen ions in hydrochloric acids

Presence of higher hydrogen ions in ethanoic acids

Presence of a higher number of hydrogen ions in hydrochloric acid than ethanoic acid

None of the mentioned

45. Describe the chemical equations when the hydroxides of Zinc and Copper (which are precipitates ) react with excess Ammonia solution to form soluble complex ions

Zn(OH)2 (S) + 4NH3 (aq) = [ Zn(NH3)4]2+(aq) + 2OH- (aq)

Cu(OH)2 (S) + 4NH3 (aq) = [Cu(NH3)4]2+(aq) + 2OH- (aq)

Both B and C

None of the mentioned

46. Water that contains dissolved salts and does not readily lather with soap is called?

Soft water

Distilled water

Hard water

None of the mentioned

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