Acids and Alkalis

Question 1

What pH is the strongest acid

Answer 1

pH 0

Question 2

What pH is the strongest alkali

Answer 2

pH14

Question 3

What is the pH of a neutral substance

Answer 3

pH 7

Question 4

What are the colours of the pH scale, from most acidic to alkali

Answer 4

Red, orange/yellow, green, blue, purple

Question 5

What are the 4 types of indicator

Answer 5

• universal indicator
• litmus paper
• phenolphthalein
• methyl orange

Question 6

What are the colours changes in litmus paper

Answer 6

Acidic - red
Neutral - purple
Alkali - blue

Question 7

Colour changes of phenolphthalein

Answer 7

Acidic - colourless
Alkali - bright pink

Question 8

Colour changes of methyl orange

Answer 8

Acidic - red
Alkaline - yellow

Question 9

Definition of acid -

Answer 9

Donates H+ ions in water. Proton donors
Acids have a pH of less than 7

Question 10

Definition of alkali -

Answer 10

a Base that Donate OH- ions in water. pH of >7

Question 11

Definition of a base -

Answer 11

A substance that can neutralise an acid. They are proton acceptors

Question 12

Allalis are ______ bases

Answer 12

soluble
An alkali is any base that is soluble in water

Question 13

Definition of neutralisation -

Answer 13

A reaction between an acid and a base / alkali to form a neutral solution of a salt and water.
- proton transfer:acid donates protons which are accepted by the base
- produces H2O
- products are netrual, have a pH7

Question 14

Example of neutralisation / acid-base reaction

Answer 14

H+ + OH- —> H20

Question 15

What is an alternative to indicator

Answer 15

pH meter
Used when solution is already coloured