C8) Acids, Bases and Salts

Question 1

What is the flame colour for lithium? (flame test)

Answer 1

red

Question 2

What is the flame colour for sodium? (flame test)

Answer 2

yellow

Question 3

What is the flame colour for potassium? (flame test)

Answer 3

lilac

Question 4

What is the flame colour for copper? (flame test)

Answer 4

blue-green

Question 5

What is the test for ammonia? (test for gases)

Answer 5

turns damp red litmus paper blue

Question 6

What is the test for carbon dioxide? (test for gases)

Answer 6

turns limewater milky

Question 7

What is the test for chlorine? (test for gases)

Answer 7

bleaches damp litmus paper

Question 8

What is the test for hydrogen? (test for gases)

Answer 8

pops with a lighted splint

Question 9

What is the test for oxygen? (test for gases)

Answer 9

relights a glowing splint

Question 10

What is the test and result for carbonate? (test for anions)

Answer 10

• add dilute acid
• effervescence, carbon dioxide produced

Question 11

What is the test and result for chloride? (test for anions)

Answer 11

• acidify with dilute nitric acid, then add aqueous silver nitrate.
• white ppt.

Question 12

What is the test and result for bromide? (test for anions)

Answer 12

• acidify with dilute nitric acid, then add aqueous silver nitrate.
• cream ppt.

Question 13

What is the test and result for nitrate? (test for anions)

Answer 13

• add aqueous sodium hydroxide, then aluminium foil; warm carefully.
• ammonia produced.

Question 14

What is the test and result for sulfate? (test for anions)

Answer 14

• acidify, then add aqueous barium nitrate.
• white ppt.

Question 15

What is the effect of ammonium on 1.aqueous sodium hydroxide & 2.aqueous ammonium? (test for cations)

Answer 15

1. ammonia produced on warming.
2. –

Question 16

What is the effect of calcium on 1.aqueous sodium hydroxide & 2.aqueous ammonium? (test for cations)

Answer 16

1. white ppt., insoluble in excess.
2. no ppt. or very slight white ppt.

Question 17

What is the effect of copper on 1.aqueous sodium hydroxide & 2.aqueous ammonium? (test for cations)

Answer 17

1. light blue ppt., insoluble in excess.
2. light blue ppt., soluble in excess, giving a dark blue solution.

Question 18

What is the effect of iron (II) on 1.aqueous sodium hydroxide & 2.aqueous ammonium? (test for cations)

Answer 18

1. green ppt., insoluble in excess.
2. green ppt., insoluble in excess

Question 19

What is the effect of iron (III) on 1.aqueous sodium hydroxide & 2.aqueous ammonium? (test for cations)

Answer 19

1. red-brown ppt., insoluble in excess.
2. red-brown ppt., insoluble in excess.

Question 20

What is the effect of zinc on 1.aqueous sodium hydroxide & 2.aqueous ammonium? (test for cations)

Answer 20

1. white ppt., soluble in excess, giving a colourless solution.
2. white ppt., soluble in excess, giving a colourless solution.

Question 21

What is pH of acids?

Answer 21

below 7

Question 22

what is the pH of bases?

Answer 22

above 7

Question 23

give 3 properties of bases.

Answer 23

• slippery in touch.
• bitter in taste.
• pH above 7.

Question 24

give 3 properties of acids.

Answer 24

• sour taste (when edible)
• are corrosive
• pH below 7.

Question 25

State the colour indicator of acids and bases for litmus paper.

Answer 25

- acids : turn litmus paper red. - bases : turn litmus paper blue.

Question 26

Give the equation for the reaction of acids with metal.

Answer 26

Acid + Metal → Salt + Hydrogen

Question 27

Give the equation for the reaction of acids with bases.

Answer 27

Acid + Base → Salt + Water

Question 28

Give the equation for the reaction of acids with metal carbonates.

Answer 28

Acid + Metal Carbonate → Salt + Carbon Dioxide + Water

Question 29

Give the equation for the reaction of bases with ammonium salt.

Answer 29

Base + Ammonium salt → Salt + Ammonia + Water

Question 30

What is an acid?

Answer 30

An acid is a substance that produces hydrogen ions, H +(aq), when dissolved in water

Question 31

What is a base?

Answer 31

An alkali is a substance that produces hydroxide ions, OH -(aq), when dissolved in water.

Question 32

What is the importance of controlling acidity in soil?

Answer 32

If it is too alkaline or acidic, the crops won't grow properly. Acidity is usually the problem for soil, so a base can help neutralise it. Bases like limestone, slaked lime, or quick lime are usually sprayed in the soil to neutralise it before planting crops.

Question 33

What is the pH number and colour for neutral?

Answer 33

- 7 - green

Question 34

what pH colour is a strong acid?

Answer 34

red

Question 35

what pH colour is a strong base?

Answer 35

dark blue/purple

Question 36

how are acidic oxides formed?

Answer 36

when a non-metal element combines with oxygen

Question 37

how are basic oxides formed?

Answer 37

when a metal element combines with oxygen

Question 38

what are neutral oxides?

Answer 38

oxides that do not react with either acids, nor bases.

Question 39

what are amphoteric oxides?

Answer 39

oxides that can behave as both acidic and basic depending on whether the other reactant is an acid or a base.