Chapter 8 - Acid Base Equilibrium Flashcards
define Arrhenius theory
a theory stating that, in an aqueous solution, an acid is a substance that produces hydrogen ions (H+) and a base is a substance that produces hydroxide ions(OH-)
what is a hydrogen ion
a hydrogen atom without an electron, a proton
why was the Arrhenius theory limited?
it allows for only one kind of base (compounds containing hydroxide ion) and it assumes all acid-base reactions occur in aqueous solutions
define brønsted-Lowry theory
a theory stating that an acid is a hydrogen ion/proton donor and a base is a hydrogen ion/proton acceptor
what does the brønsted-lowry theory apply to?
all of the Arrhenius acids and bases and some others not categorised as acids and bases under the Arrhenius theory
what is an example of a base not categorized as one under the Arrhenius theory definition
NH3, does not contain hydroxide ions, but is a base
how is an acid usually produced?
dissolving the compound in water
what ions does the Arrhenius theory predict will be produced when an acid is dissolved in water?
hydrogen ions
what does experimental evidence disprove about Arrhenius’s theory of hydrogen ions being produced?
hydrogen ions are not stable on their own, they react with the water molecule to form a hydronium ion
define a hydronium ion
a water molecule that has accepted a hydrogen ion (H30+)
what atom in the water molecule pulls a hydrogen ion away from the molecule and why?
oxygen because it has two lone electron pairs, one of the pairs forms a coordinate covalent bond with the donated hydrogen ion
what kind of equilibrium is it when explaining the brønsted-lowry theory and what kind of reaction is it?
a reversible reaction resulting in a dynamic equilibrium
what is water in an acidic solution?
a proton acceptor, a base
what is water in basic solutions?
a proton donator, an acid
what is responsible for the acidic properties of an acidic solution
dissolved hydronium ions
what is responsible for the basic properties of a basic solution
hydroxide ions
what happens because an acid-base reaction is reversible
a hydrogen ion (proton) transfer may occur in the forward and reverse reaction
general equation for the equilibrium reaction of an acid with water to form an acidic solution
HA (aq) + H20 (l) ⟶ A-(aq) + H30+ (aq)
define conjugate acid
the substance that forms when a base, according to brønsted-lowry theory, accepts a hydrogen ion (proton)
define conjugate base
the substance that forms when an acid loses a hydrogen ion (proton)
what does the hydronium ion act as in an acidic solution?
conjugate acid
general equation for the equilibrium reaction of a base with water to form a basic solution
B (aq) + H20 (l) ⟶ HB+ (aq) + OH- (aq)
what doe the hydroxide ion act as in a basic solution
conjugate base
define conjugate-base pair
two substances related to each other by the donating and accepting of a single hydrogen ion
what states can acid-base reactions occur in brønsted-lowry theory?
non-aqueous states and aqueous states
give an example of an acid base reaction in a non aqueous state
HCl (g) + NH3 (g) ⟶ NH4Cl (s) (or NH4+ (s) + Cl- (s))
what is another term for amphiprotic?
amphoteric
define amphiprotic
able to donate or accept a hydrogen ion (proton) and thus act as both a Brønsted-Lowry acid and a Brønsted-Lowry base
2 amphiprotic substances
water and hydrogen carbonate ion (HCO3- (aq)
2 reaction where water and hydrogen carbonate ions are amphiprotic, including whether they act as bases or acids
HCO3- (aq) (base) + H20 (l) (acid) ⟶ H2CO3+ (aq) (conjugate acid) + OH-(aq) (conjugate base) and HCO3- (aq) (acid) + H20- (l) (base) ⟶ CO3^2- (aq) (conjugate base) + H30+ (aq) (conjugate acid)
