ACID Base theories and conjugate pairs Flashcards
(9 cards)
Properties of acids
sour
conducts electricity
no feel
turns red with litmus
stays clear with phenolphthalein
Properties of bases
Bitter
Conducts electricity
Slippery
Turns blue with litmus
Turns pink with phenophthalein
Arrhenius Theory of Acids and Bases
Named after a Swedish chemist Svante Arrhenius
He stated that an acid is a substance that dissociates in water to produce one or more hydrogen ions, H+
A base is a substance that dissociates in water to form one or more hydroxide ions, OH-
Why the Arrhenius Theory is Garbage…
Protons do not actually exist in isolation in aqueous solutions, they are hydrated (H3O+ - hydronium ion)
Ammonia, a known base, does not contain hydroxide ions:
Theory is limited to acid-base reactions in water (these can take place in other solvents!)
The Bronsted-Lowry Theory of Acids and Bases
An acid is a substance from which a proton (H+ ion) can be removed
A base is a substance that can remove a proton (H+ ion) from an acid
Like an Arrhenius acid, a Bronsted-Lowry acid MUST contain H in its formula.
However, any negative ion (not just OH-) can be a Bronsted-Lowry base.
For a Bronsted-Lowry acid-base reaction
one substance must provide a proton, and another substance must receive the same proton.
Thus, according to this theory, any substance can behave as an acid, as long as another substance is behaving like a base at the same time!
Conjugate Acid-Base Pairs
Two molecules or ions that are related by the transfer of a proton
The CONJUGATE BASE of an acid is the particle
That remains when a proton is removed from the acid.
The CONJUGATE ACID of a base is the particle
that results when the base receives the proton from the acid.
