3.9 Acid-Base Equilbiria

Question 1

Describe the Lowry-Bronsted theory

Answer 1

• acid base equilibria involve the transfer of protons between substances
• a Lowry-Bronsted acid is a proton donor
• a Lowry-Bronsted base is a proton acceptor

Question 2

Strong acid vs weak acid

Answer 2

Strong: completely dissociates into its ions
Weak: partially dissociates

Question 3

What is the equilibrium dissociation constant?

Answer 3

Ka

Question 4

Describe the relationship between Ka and acid strength

Answer 4

• stronger acid = higher Ka value
• strong acids dissociate to ions more, meaning the concentration of ions at equilibria is much greater making Ka increase in value

Question 5

When is methyl orange used?

Answer 5

• reactions with a more acidic neutralisation point
• red in acids and turns yellow at neutralisation point

Question 6

When is phenolpthaliein used?

Answer 6

• reactions with more basic neutralisation point
• pink in alkali and turns colourless at neutralisation point