Acids and Bases Quiz 2 Flashcards
In the context of Bronsted – Lowry acid – base theory, what is a “polyprotic acid”
A polyprotic acid is an acid that can transfer two or more hydrogen ions (H+) during an acid – base reaction.
Explain why the number of hydrogen atoms present in one molecule of an acid cannot always be
used to classify the molecule as monoprotic, diprotic, triprotic, or even polyprotic.
Not all of the hydrogen atoms in a molecule are involved in chemical bonds that allow them to be
removed from the atom.
In the context of Bronsted – Lowry acid – base theory, what is an “acidic hydrogen atom”?
An acidic hydrogen atom is a hydrogen atom in an acid molecule that can be transferred to a base
during an acid base reaction.
Compare acidic hydrogen atoms and nonacidic hydrogen atoms with respect to their locations on
their parent molecules.
The acidic hydrogen atoms tend to be bonded to elements like oxygen and other highly
electronegative elements while nonacidic hydrogen atoms tend to be bonded to carbon and
elements with lower electronegativities.
The acidic hydrogen atoms tend to be bonded to elements like oxygen and other highly
electronegative elements while nonacidic hydrogen atoms tend to be bonded to carbon and
elements with lower electronegativities.
Bases that are able to accept more than one acidic hydrogen from a Bronsted – Lowry base must
have more than one pair of lone electrons that can be used to form a coordinate covalent bond with
an incoming hydrogen ion (H+)
In the context of Bronsted – Lowry acid – base theory, characterize a strong acid.
a strong acid is an acid that transfers 100%, or
very nearly 100% of its acidic hydrogen atoms to a nearby water molecule when in aqueous
solution.
In the context of Bronsted – Lowry acid – base theory, characterize a weak acid.
a weak acid is an acid that transfers only a small
percentage of its acidic hydrogen atoms to a nearby water molecule when in aqueous solution.
In the context of Bronsted – Lowry acid – base theory, upon what factors does the actual
percentage of molecules involved in proton transfer from the acid to water depend?
The molecular structure of the acid molecules.
The molecular polarity of the acid molecules
The strength of the chemical bonds in the acid molecules.
The polarity of the chemical bonds in the acid molecules.
In the context of Bronsted – Lowry acid – base theory, what is a “conjugate acid – base pair”?
A conjugate acid – base pair is two species, one an acid and one a base, that differ from each other
through the loss or gain of a single hydrogen ion (H+).
Explain the relationship between an acid and its conjugate base.
An acid loses a hydrogen ion (H+) in the forward reaction and becomes its own conjugate base in
the reverse reaction when it acquires a hydrogen ion.
In the context of Bronsted – Lowry acid – base theory, what is an “amphiprotic substance”?
An amphiprotic substance is a substance that can either lose or gain a hydrogen ion (H+) and thus
can function as either an acid or a base.
What are the two structural requirements for all amphiprotic substances; that is, what must all
amphiprotic substances have?
For a substance to be amphiprotic, it must be able to lose or accept a hydrogen ion (H+) and must
therefore have a hydrogen atom to lose as well as a nonbonding pair of electrons to accept a
hydrogen ion from another substance.
