Chapter 6 (6.7 - 6.8)

Question 1

What is neutralisation?

Answer 1

A: The reaction of an acid with a base or alkali to form salt and water.

Question 2

What is the neutralisation reaction between hydrochloric acid and sodium hydroxide?

Answer 2

HCl + NaOH →NaCl + H2O

Question 3

What is the reaction between sulfuric acid and copper(II) oxide?

Answer 3

H2SO4 + CuO →CuSO4 +H2O

Question 4

Write the reaction between nitric acid and calcium hydroxide.

Answer 4

2HNO3 + Ca(OH)2 → Ca(NO3)2 +H2O

Question 5

Name one application of neutralisation in industry.

Answer 5

Calcium carbonate is used to remove acidic gases such as sulfur dioxide before they are released into the air.

Question 6

What is the titration method?

Answer 6

A quantitative analysis method to determine the volume of acid needed to neutralise a given volume of alkali (or vice versa).

Question 7

What is the endpoint in titration?

Answer 7

The point where the acid-base indicator changes color, indicating neutralisation.

Question 8

What apparatus is used in a titration setup?

Answer 8

Burette (holds the acid or base).
Conical flask (contains the other reactant and indicator).
Retort stand (supports the burette).
White tile (to observe color change).

Question 9

What is the role of an indicator in titration?

Answer 9

A: To signal the endpoint by changing color when neutralisation occurs.

Question 10

What color does phenolphthalein show in an acidic and neutral solution?

Answer 10

A: Colorless.

Question 11

What color does phenolphthalein show in an alkaline solution?

Answer 11

A: Light pink.

Question 12

What color does methyl orange show in an acidic solution?

Answer 12

A: Red.

Question 13

What color does methyl orange show in an alkaline solution?

Answer 13

A: Yellow.

Question 14

What color does methyl orange show in a neutral solution?

Answer 14

A: Orange.

Question 15

What is the pH range for phenolphthalein?

Answer 15

A: It changes color in the pH range of 4.8 to 7.0.

Question 16

What is the pH range for methyl orange?

Answer 16

A: It changes color in the pH range of 3.4 to 4.4.

Question 17

What is a strong acid-strong base neutralisation reaction?

Answer 17

It results in the formation of neutral salt and water
(e.g., HCl + NaOH → NaCl + H₂O

Question 18

What is a weak acid-strong base neutralisation reaction?

Answer 18

A: It results in the formation of a basic salt and water
(e.g., CH₃COOH + NaOH → CH₃COONa + H₂O).

Question 19

What is a strong acid-weak base neutralisation reaction?

Answer 19

It results in the formation of an acidic salt and water
(e.g., HCl + NH₃ → NH₄Cl + H₂O).

Question 20

What is a weak acid-weak base neutralisation reaction?

Answer 20

It results in the formation of a neutral salt and water
(e.g., H₂CO₃ + NH₄OH → NH₄CO₃ + H₂O).

Question 21

What factors affect the rate of neutralisation?

Answer 21

Concentration of reactants.
Temperature (higher temperature speeds up reactions).
Surface area of the solid reactant.
Stirring to evenly mix the reactants.

Question 22

What is the definition of salt?

Answer 22

An ionic compound formed when the hydrogen ion (H⁺) from an acid is replaced by a metal ion or ammonium ion (NH₄⁺).

Question 23

What is formed when an acid reacts with a base (alkali)?

Answer 23

A: Salt and water. This is a neutralisation reaction.

Question 24

What happens when an acid reacts with a reactive metal?

Answer 24

Salt and hydrogen gas are produced.

Question 25

What is the result of the reaction between an acid and a metal carbonate?

Answer 25

Salt, water, and carbon dioxide are produced.

Question 26

What is formed when an acid reacts with aqueous ammonia?

Answer 26

Ammonium salt is produced.

Question 27

What is the use of ammonium nitrate in agriculture?

Answer 27

It is used as a fertiliser.

Question 28

What is the use of iron(II) sulphate in agriculture?

Answer 28

A: It is used as a pesticide.

Question 29

How is calcium sulphate used in medicine?

Answer 29

It is used to make Plaster of Paris to support broken bones.

Question 30

What is the use of potassium manganate(VII) in medicine?

Answer 30

It is used as an antiseptic to treat wounds.

Question 31

How is sodium chloride used in food?

Answer 31

It is used as a food flavouring.

Question 32

What is the use of sodium bicarbonate in food?

Answer 32

It is used for raising dough in baking.

Question 33

How is sodium benzoate used in preservation?

Answer 33

It is used to preserve chilli sauce.

Question 34

What is the use of sodium nitrate in preservation?

Answer 34

A: It is used to preserve processed meat (e.g., sausages).