Strong acids and strong bases always react in the same format since the dissociate nearly 100% in water. Solutions of hydrochloric acid and sodium hydroxide are mixed the reaction occurs as follows: Weak acids dissociate only slightly in water, and therefore should be left combined and not written as its ions.  When weak acids react with strong bases, the H+ from the weak acid is transferred to the OH- from the strong base to form water and a salt.  The salt formed, however, will most likely be soluble, and should be written as its respective ions.  Remember also, to cancel out any spectator ions.

1. ACID –BASE
REACTION

2.  Strong acids and strong bases always
react in the same format since the
dissociate nearly 100% in water.
 Solutions of hydrochloric acid and sodium
hydroxide are mixed the reaction occurs
as follows:

3.  According to the solubility rules, these
compounds in aqueous solution
dissociate to form their ions. Ions which
are found on both sides of the reaction
(spectator ions) can be cancelled out
because they are unchanged by the
reaction.

4.  The final answer for all strong acid-strong
base reactions is:

5. Common Strong Acids Common Strong Bases
Formula Name Formula Name
HI hydroiodic acid NaOH sodium hydroxide
HBr hydrobromic acid LiOH lithium hydroxide
HCl hydrochloric acid KOH potassium hydroxide
HClO4 perchloric acid RbOH rubidium hydroxide
H2SO4 sulfuric acid Sr(OH)2 strontium hydroxide
HSCN thiocyanic acid Ba(OH)2 barium hydroxide
HNO3 nitric acid
H2CrO4 chromic acid

6. Common Weak Acids
Acid Formula
Formic HCOOH
Acetic CH3COOH
Trichloroacetic CCl3COOH
Hydrofluoric HF
Hydrocyanic HCN
Hydrogen
sulfide
H2S
Water H2O
Conjugate acids
of weak bases
NH4
+
Common Weak Bases
Base Formula
ammonia NH3
trimethyl
ammonia
N(CH3)3
pyridine C5H5N
ammonium
hydroxide
NH4OH
water H2O
HS- ion HS-
conjugate bases
of weak acids
e.g.:
HCOO-

7.  Weak acids dissociate only slightly in water, and
therefore should be left combined and not
written as its ions. When weak acids react with
strong bases, the H+ from the weak acid is
transferred to the OH- from the strong base to
form water and a salt. The salt formed, however,
will most likely be soluble, and should be written
as its respective ions. Remember also, to cancel
out any spectator ions.

8.  Solutions of potassium hydroxide and
acetic acid are mixed.

9.  A solution of hydrofluoric acid is added to
sodium hydroxide

10.  Ammonia (NH3) is a strong base that has
its own type of reaction. When it reacts
with a strong acid, the H+ from the acid is
transferred to the ammonia to form the
NH4
+ ion. The rest of the strong acid acts
only as a spectator ion and can be
cancelled out.

11.  A solution of ammonia is mixed with a
solution of nitric acid.

12.  Solutions of ammonia and sulfuric acid
are mixed

13.  The only difference when ammonia reacts
with a weak acid instead of a strong acid
is that the acid does not dissociate. The
acid is left combined and is not written as
ions.

14.  A solution of ammonia is added to a
solution of hydrofluoric acid.

15.  Solutions of ammonia and carbonic acid
are mixed

16.  Strong acids react with salts to form weak
acids. The H+ from the acid is transferred
to the anion (negative ion) of the salt to
form the weak acid. Remember to write
the strong acids and the soluble salts as
their respective ions and cancel out any
spectator ions.

17.  A solution of hydrochloric acid is mixed
with a solution of sodium bicarbonate.

18.  Dilute sulfuric acid is added to a solution
of lithium fluoride.

19.  Excess hydrobromic acid is added to a
solution of potassium sulfide.
 NOTE: Because there is excess acid, as
much H+ will bond with the anion as
possible.

20.  Ammonium salts react with strong bases
to form water and ammonia. The H+ from
the ammonia in the salt is transferred to
the OH- in the base. Remember to write
the strong bases and soluble salts as their
respective ions and to cancel out any
spectator ions.

21.  A solution of potassium hydroxide is mixed
with a solution of ammonium nitrate.

22.  Solutions of sodium hydroxide and
ammonium chloride are mixed.

23.  When a nonmetal oxide gas is bubbled through
a strong basic solution, the nonmetal oxide
reacts first with the water to form an
intermediate which reacts with the base. Two
separate equations can be written and "added"
together to get a third. The third equation
should be simplified to cancel out any ions or
molecules that are found on both sides of the
equation. Remember also to write soluble salts
and strong bases as their respective ions and
cancel out any spectator ions.

24.  Sulfur trioxide gas is bubbled through a
potassium hydroxide solution.