Important : Acids, Bases, Salts

Question 1

Definition of acid

Answer 1

Substance reacts with water to release H+ ions

Question 2

Definition of base

Answer 2

Substance that react with acids to form salt & water ( & sometimes CO2 )

Question 3

Definition of alkali

Answer 3

Base that reacts with water to release OH- ions

Question 4

Definition of salt

Answer 4

Ionic substance formed when acids react with bases

Question 5

List 5 common acids

Answer 5

1. Hydrochloric acid
2. Sulfuric acid
3. Nitric acid
4. Phosphoric acid
5. Ethanoic acid

Question 6

Formula of hydrochloric acid

Answer 6

H Cl

Question 7

Formula of sulfuric acid

Answer 7

H2 SO4

Question 8

Formula of nitric acid

Answer 8

H NO3

Question 9

Formula of phosphoric acid

Answer 9

H3 PO4

Question 10

Formula of ethanoic acid

Answer 10

CH3 COOH

Question 11

Rule for a strong acid and formula

Answer 11

Rule = all molecules ionise

Formula = ???

Question 12

Rule and formula for weak acid

Answer 12

Rule = small fraction of molecules ionise

Formula ???

Question 13

List 2 common bases and give examples

Answer 13

1. Metal oxides eg. CaO

2. Metal carbonates eg. Na2 CO3

Question 14

List 2 commons alkali

Answer 14

1. Ammonia ( NH3)

2. Metal Hydroxides ( OH- )

Question 15

List 6 common salts

Answer 15

1. Chlorides
2. Sulfates
3. Nitrates
4. Phosphates
5. Ethanoates
6. Citrates

Question 16

Metal + acid = ?

Answer 16

Salt + hydrogen

Question 17

Metal oxide + acid =?

Answer 17

Salt + water

Question 18

Metal hydroxide + acid =?

Answer 18

Salt + water

Question 19

Metal carbonate + acid =?

Answer 19

Salt + water + carbon dioxide

Question 20

Ammonia + acid =?

Answer 20

Ammonium salt

Question 21

Name 5 indicators ( acid / alkali tests)

Answer 21

1. Universal indicator
2. Methyl orange
3. Phenolphthalein
4. Litmus paper
5. ???

Question 22

Universal indicator colour changes

Answer 22

Rainbow colours:

Strong acid = red

Neutral = green

Strong alkaline purple

Question 23

Methyl orange colour changes

Answer 23

Acidic = red
Alkaline = yellow

Question 24

Phenolphthalein colour changes

Answer 24

Acidic = colourless 
Alkaline = bright pink

Question 25

Litmus paper colour changes

Answer 25

Acidic = red
Neutral = purple
Alkaline = blue

Question 26

pH scale range

Answer 26

0-14

Strongest acid = 0
Neutral = 7
Strongest alkaline = 14