Acid Base Equill Flashcards
What is an Arrhenius acid
It is a substance that dissolves in water to release H+ ions
What is an Arrhenius base
It is a substance that dissolves in water to release OH- ions
By the Arrhenius Theory, acid-base reactions can only take place in what medium
Aqueous medium (water as solvent)
What is a Bronsted acid
A Bronsted acid is a proton, H+, donator
What is a Bronsted base
A Bronsted base is a proton, H+, acceptor
What are amphoteric solvents
An amphoteric solvent can both donate and accept protons durinfg different conditions
They can act as both Bronsted acids and bases.
E.g: water
During a reversible reaction that is also an acid-base reaction, what is the reactant-product pair called
A conjugate acid-base pair
How do the members of the conjugate acid-base pair differ
They differ from each other in terms of a H+
What is a lewis acid
A lewis acid is an electron-pair acceptor
What is a lewis base
A lewis base is an electron-pair donator
Are the Arrhenius acids a subset of Lewis acids
Yes
Are the Arrhenius acids a subset of Bronsted acids
Yes
Are Bronsted acids a subset of Lewis acids
Yes
What is the strength of an acid dependant on
The extent of dissociation in an aqueous medium
What is a strong acid and a weak acid
(i) A strong acid is an acid that will completely dissociate in aqueous medium
(ii) A weak acid is an acid that will not completely dissociate in aqueous medium
What is the significance of a reversible acid-base reaction
The acid is a weak acid or the base is a weak base.
What is a strong base and what is a weak base
(i) A strong base will completely ionise in aqueous medium
(ii) A weak base will partially ionise in aqueous medium
What is an indicator of strength of acid
Extent of dissociation A (alpha) which is derived from [H3O+]equil./[Acid]ini
Why is the extent of dissociation not a very accurate measurement of strength
It increases with decreasing concentration
Why is concentration not a good indicator of strength of an acid
Concentration is not equivalent to extent of dissociation.
(i) concentration refers to the amount of acid dissolved in an aqueous medium
(ii) extent of dissociation refers to the ratio between concentration of acid dissociated to concentration of acid initially
What is the Kc expression of the auto-ionisation of water
Kc=[H3O+][OH-]/[H2O]^2
What is the significance of the Kw value
(i) At a temperature of 25°C, the product of [H3O+] and [OH-] will always be this value
(ii) For reactions involving the dissociating of acids and ionisation of bases, a change in [H3O+] will induce an inversely proportional change in [OH-] and vice versa
What is the pH solution of an alkalinic solution
pH>7, where [OH-] is greater than 10^-7
What is the pH level of an acidic solution
pH<7, [H3O+]>10^-7
Logarithmic relationship between concentrations of [H3O+] and [OH-]
-14=log[OH] + log[H3O+]
Given that auto-ionisation of water is endothermic, what is the relationship between the pH of water and temperature
Thought process
Suppose there is an increase in temperature,
(i) By Le Chatelier’s principle, the endothermic reaction would be favoured
(ii) [H3O+], [OH-] falls
(iii) pH= -log[H3O+], thus pH falls
Thought process regarding calculations of pH of strong acids and bases
(i) Find concentration of strong acid or bases
(ii) Concentration of [H3O+] or [OH-] dependant on basicity
(iii) Using pH formula, find pH
Thought process for calculation of pH of weak acid or weak base
(i) Using formula [H3O+]=(Ka×c)^0.5, find [H3O+], if base replace products and replace Ka with Kb
(ii) Use pH formula
What is the
