MODULE 5: Acids, Bases and pH

Question 1

Bronsted-Lowry model of acids:

Answer 1

Acids are proton donators

Question 2

Bronsted-Lowry model of bases:

Answer 2

Bases are proton acceptors

Question 3

Conjugated acid-base pair:

Answer 3

Consists of two substances that differ only by the presence of a proton (H⁺)
e.g. HCl releases a proton to form the conjugated base Cl-, Cl- accepts a proton to form a conjugated acid HCl

Question 4

Conjugated acid-base pair of neutralisation:

Answer 4

HX + OH- –> H2O + X-
OH- = conjugated base
H2O = conjugated acid

Question 5

Reaction of acids with metals:

Answer 5

acid + metal = salt + hydrogen gas

Question 6

Neutralisation of acids with carbonates:

Answer 6

acid + carbonate = salt + water + carbon dioxide gas

Question 7

Neutralisation of acids with metal oxides:

Answer 7

acid + metal oxide = salt + water

Question 8

Neutralisation of acids with alkalis:

Answer 8

acid + alkali = salt + water

Question 9

pH definition:

Answer 9

pH = -log10[H⁺]

Question 10

Converting from pH to concentration of H⁺:

Answer 10

10^-pH

Question 11

pH of strong acids:

Answer 11

Concentration of the acid is equal to the concentration of H⁺ as they fully dissociate

Question 12

Acid dissociation constant (Ka):

Answer 12

Exactly the same as the rate equation, except used for weak acids to display the concentration of H⁺