Acids & Alkalis F4 Flashcards
1
Q
Definition of an indicator
A
An indicator is a chemical which is one colour in acid and another in alkali
2
Q
Red litmus in acid
A
Stays red
3
Q
Red litmus in alkali
A
Turns blue
4
Q
Blue litmus in acid
A
Turns red
5
Q
Blue litmus in alkali
A
Stays blue
6
Q
Phenolphalein in acid
A
Stays colourless
7
Q
Phenolphalein in alkali
A
Turns pink
8
Q
Methyl Orange in acid
A
Turns pink
9
Q
Methyl Orange in alkali
A
Turns yellow
10
Q
Advantages of an indicator
A
- Shows different colours for acids and alkalis
11
Q
Disadvantages of an indicator
A
- Don’t tell us relative strengths
- Limited in their use
12
Q
Universal indicators
A
Indicate the STRENGTH of the substance
13
Q
pH of strong acid
A
0 - 2
14
Q
pH of weak acid
A
3 - 6
15
Q
pH of weak alkali
A
8 - 11
16
Q
pH of strong alkali
A
12 - 14
17
Q
Strong Acids
A
- Hydrochloric Acid
- Nitric Acid
- Sulfuric Acid
18
Q
Weak Acids
A
- Ethanoic Acid
- Carbonic Acid
19
Q
Neutral Substances
A
- Water
- Petrol
- Ethanol
20
Q
Weak Alkalis
A
- Ammonia