6. Acids and Bases

Question 1

What are the 4 types of oxides

Answer 1

Basic Oxide
Neutral Oxide
Acidic Oxide
Amphoteric Oxide

Question 2

List 7 properties of Acids

Answer 2

1. Tastes sour
2. Turns blue litmus paper to red litmus paper
3. Reacts with metals to form hydrogen gas
4. Forms H+ Ions
5. pH less than 7
6. Neutralises bases
7. Good conductors of electricity

Question 3

List 5 properties of Bases

Answer 3

1. Slippery, bitter
2. Turns red litmus paper blue
3. Usually forms OH- Ions
4. Neutralises acids
5. pH is greater than 7

Question 4

How do acids react with metals?

Answer 4

acid + metal -> salt + hydrogen

Question 5

Hydrochloric acid + base

Answer 5

Salts are chloride

For example:

Hydrochloric acid + Sodium hydroxide → Sodium chloride + Water
HCl+NaOH → NaCl+H₂O HCl+NaOH→NaCl+H₂O

Question 6

Nitric acid + Base

Answer 6

Nitrates are formed
Example?

Question 7

Sulphuric acid + Base

Answer 7

Sulphates are formed
Example?

Question 8

How do acids react with bases? What products do they form?

Answer 8

Neutralise the base.
acid+base—> salt+water

Question 9

How do acids react with metal carbonates?

Answer 9

Acid + metal carbonate –> salt + water + carbon dioxide

Question 10

How to test for Hydrogen gas?

Answer 10

When a lighted splint is inserted, a pop sound is heard

2H2(g) + O2(g) -> 2H2O(l)

Question 11

How to test for Carbon Dioxide gas?

Answer 11

When bubbled through limewater, the limewater turns cloudy

Question 12

Lime water

Answer 12

Calcium Hydroxide Ca(OH)2

Question 13

What is the product of lime water+ CO2

Answer 13

CaCO3, it is insoluble in water and thus becomes milky

Question 14

Element reacting with Oxygen form?

Answer 14

Oxides

Question 15

How to test for Ammonia?

Answer 15

Damp red litmus paper turns blue as ammonia is a weak base.

Question 16

How to test for Oxygen?

Answer 16

Relights a glowing splint

Question 17

How to test for Chlorine?

Answer 17

Bleaches damp blue litmus paper

Because it forms acids with water that first turn the paper red, then bleach out the color completely

Question 18

Give 2 examples of strong acids

Answer 18

Hydrochloric Acid (HCl)
Sulfuric Acid (H2SO4)

Question 19

2 examples of weak acids

Answer 19

Citric acid
Carbonic acid
Ethanolic acid (CH3COOH)

Question 20

2 examples of strong bases

Answer 20

NaOH (Sodium Hydroxide)
KOH (Potassium Hydroxide)

Question 21

Give 2 examples of weak bases

Answer 21

NH3 (Ammonia- cleaning product)
CH3NH2 (Methylamine- used in pesticides)

Question 22

Basic Oxide

Answer 22

Metal oxides that react with water to form bases (alkalis).
Examples: Na₂O, CaO, MgO

Question 23

Neutral Oxide

Answer 23

Non-metal oxides that do not react with acids or bases
Examples: CO, NO, N₂O

Question 23

Alkali

Answer 23

A base that dissolves in water

Question 24

Acidic Oxide

Answer 24

Non-metal oxides that react with water to form acids Examples: CO₂, SO₂, NO₂, P₄O₁₀

Question 25

Amphoteric Oxide

Answer 25

Metallic Oxides which react with acids and alkalis

Question 25

Amphoteric substance

Answer 25

A substance that can act as both an acid and a base

Question 26

Example of an amphoteric substance

Answer 26

Water (H2O)

Question 27

Universal Indicator

Answer 27

More specific pH value (universal indicator colour chart) Acid = Red Neutral = Green Base = Purple

Question 27

Litmus Indicator

Answer 27

Acid = Red Alkali = Blue

Question 28

Phenolphthalein Indicator

Answer 28

Acid= Colourless Neutral= Light Pink Base= Dark pink Used in strong base-weak acid titrations

Question 29

Methyl Orange Indicator

Answer 29

Acid= Red Neutral= Yellow orange Base= Yellow Used in weak base-strong acid titrations

Question 30

Apparatus for titration

Answer 30

Burette and Pipette and Conical flask

Question 31

Soluble Salts making

Answer 31

acid+base acid+metal acid+metal carbonate

Question 32

What is an Acid?

Answer 32

A compound that increases the concentration of hydrogen ion (H +) in aqueous solution

Question 33

What is a Base?

Answer 33

A compound that increases concentration of hydroxide ions (OH -) in a water-based solution