S3 Acids&Bases

Question 1

What gives acids their properties?

Answer 1

H+ ions

Question 2

Define acid.

Answer 2

An acid is a substance which produces H+ ions when dissolved in water.

Question 3

What is the difference in definition of strong acids and weak acids?

Answer 3

Strong acids dissolve completely in water while weak acids dissolve partially in water.

Question 4

Name 3 physical properties of acids.

Answer 4

1) Has a sour taste
2) Turns damp BLUE litmus paper RED
3) Electrical conductivity(because of mobile ions)

Question 5

Define salts.

Answer 5

A salt is a compound obtained when the hydrogen of an acid is partly or completely replaced by a METAL or an ammonium ion.

Question 6

Define base.

Answer 6

A base is a metal oxide or hydroxide that reacts with an acid to form salt and water only.

Question 7

What is neutralisation?

Answer 7

When a base reacts with an acid to form salt and water.

Question 8

What happens when a base is soluble in water?

Answer 8

It will form an alkali.

Question 9

Define alkali.

Answer 9

An alkali is a base which is soluble in water and produces HYDROXIDE ions in water.

Question 10

What is the difference in definition between strong and weak alkalis?

Answer 10

Strong alkalis completely dissociate in water and produces high concentration of HYDROXIDE ions in water while weak alkalis partially dissociate in water to produce low concentration of HYDROXIDE ions.

Question 11

Name 2 examples of a strong alkali.

Answer 11

NaOH and KOH

Question 12

Name an examples of a weak alkali.

Answer 12

Ammonia solution

Question 13

Name 5 properties of an alkali.

Answer 13

1) Bitter taste
2) turns damp RED litmus paper BLUE
3) Reacts with acid to form salt and water
4) Reacts with ammonium salts to form ammonia gas, salt and water
5) Conductor of electricity due to mobile ions

Question 14

What is the color of Methyl orange in strong acids and strong alkalis?

Answer 14

acids - red

alkalis - yellow

Question 15

What is the color or phenolphthalein in strong acids and strong alkalis?

Answer 15

acids - colorless

alkalis - pink

Question 16

What is the color or screened methyl orange in strong acids and strong alkalis?

Answer 16

acids - violet

alkalis - green

Question 17

Name 3 properties of basic oxides.

Answer 17

1) oxides of metals
2) Dissolve in water to form alkalis
3) React with acids to form salt and water only

Question 18

How can oxides be classified?

Answer 18

Acidic oxides, basic oxides, amphoteric oxides, neutral oxides

Question 19

Name 3 properties of acidic oxides.

Answer 19

1) oxide of non metals
2) dissolve in water to form acids
3) React with bases to form salts and water only

Question 20

Name a property of neutral oxides.

Answer 20

Neither acidic or basic

Question 21

Name 2 examples of basic oxides.

Answer 21

CaO, CuO

Question 22

Name 4 examples of amphoteric oxides.

Answer 22

Al2O3, PbO, ZnO, SnO (tin)

Question 23

Name 2 examples of acidic oxides.

Answer 23

CO2, SO2

Question 24

Name 2 examples of neutral oxides.

Answer 24

Water, carbon monoxide

Question 25

How do we apply acids/bases in real life?

Answer 25

If the soil is too acidic, it can be neutralized by adding Ca(OH)2 (slake lime) or CaO (quicklime, known as liming the soil.

Question 26

What is a displacement reaction?

Answer 26

Acid+reactive metals=salt+hydrogen

Question 27

What is a neutralization reaction

Answer 27

Acid+bases=salt+water

Question 28

What are the products of an acid and carbonate reaction?

Answer 28

Salt, carbon dioxide and water

Question 29

Name 2 uses of acid.

Answer 29

H2SO4 used for battery acids in cars and agriculture fertilizers.

Question 30

Name 2 properties of amphoteric oxides.

Answer 30

1) metallic oxides which can behave as both acidic and basic oxides
2) form salts with both acids and alkalis.

Question 31

Explain why it becomes more difficult to see the cross when an insoluble, colored product is formed.

Answer 31

The insoluble product does not dissolve in the solution. As the reaction progresses, more and more product particles are SUSPENDED in the solution, obscuring the cross thus making it harder to see the cross.