The Brønsted-Lowry Theory Flashcards
an acid is
a proton (H+) donor
a base is
a proton (H+) acceptor
a conjugate acid-base pair consists of
either a base and its conjugate acid or an acid and its conjugate base
a conjugate acid of a base is
the species formed when a base accepts a proton
a conjugate base of an acid is
the species formed when an acid donates a proton
an amphoteric substance is
a substance than can act both as an acid and as a base
examples are: water
in the Brønsted-Lowry theory, acids and bases are defined by
the way they react with each other
a substance only behaves as an acid if the hydrogen carries
a slight positive charge
hydrogen has a slight positive charge when it is bonded to
a highly electronegative atom in the right side of the Periodic table, such as oxygen or a halogen
in order to accept a proton, a base must have
a lone pair of electrons
the lone pair of electrons in the base is used to form a
dative covalent bond with the proton (H+)
therefore, bases must contain an element from the …………side of the Periodic table which has a lone pair, usually……………
right hand side
oxygen
when hydrogen chloride dissolves in water, the following equilibrium reaction takes place:
HCl(aq) + H2O(l) ⇌ H3O (aq) + Cl-(aq)
HCl(aq) + H2O(l) ⇌ H3O (aq) + Cl-(aq)
- In the forward reaction, the HCl acts as ………………because: ………………….and the H2O acts as…………….because……..
- In the reverse reaction, the H3O+ acts as…………because…………….and the Cl- acts as…………………because
HCl(aq) + H2O(l) ⇌ H3O (aq) + Cl-(aq)
- HCl acts as an acid because it donates a proton to the H2O
- H2O acts as a base because is accepts a proton from the HCl
- H3O+ acts as an acid because it donates a proton to the Cl-
- Cl- acts as a base because it accepts a proton from the H3O+
identify the conjugate acid-base pairs in the following reaction:
HCl(aq) + H2O(l) ⇌ H3O (aq) + Cl-(aq)
- HCl and H2O
- H3O+ and Cl-
Identify the conjugate pairs in the following reaction:
HCl(aq) + H2O(l) ⇌ H3O (aq) + Cl-(aq)
- Cl- is the conjugate base of HCl
- H2O is the conjugate base of H3O+
a diprotic or dibasic substance is
an ACID that can donate two protons, such as H2SO4
sulfuric acid is dibasic. write down the two steps for the reaction of sulfuric acid to donate two H+ ions
H2SO4 = H+ + HSO4- HSO4- = H+ + SO4 2-
a diprotic or diacid substance is
a BASE that can accept two protons, such as CO3 2-
the reaction of the carbonate ion to receive two protons is:
CO3 2- + H+ = HCO3-
HCO3- + H+ = H2CO3
- when ammonia dissolves in water, an equilibrium is established, shown in the equation:
- identify the conjugate acid-base pairs
NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq)
NH3 and NH4+
H2O and OH-
in the reaction with HCl, H2O acts as……………..because it…………..a proton while in the reaction with NH3, H2O acts as ………………because it……………….a proton. Therefore water is described as being ………………………
- H2O is a base with HCl as it accepts a proton
- H2O is an acid with NH3 as it donates a proton
- Amphoteric or amphiprotic
all……………are……………………but not all……………………….are……………………
all amphiprotic substances are amphoteric but not all amphoteric substances are amphiprotic
amphiprotic substances are those that
can both donate and accept protons
examples are: water, amino acids and HSO4- (hydrogensulfate ion)
an acid can also be described as being an
electron pair acceptor
a base can also be described as being an
electron pair donor
