The Foundations of Chemistry

19-8 Summary of Acid–Base Calculations 817

TABLE 19-7 A Review of Our Understanding of Nonneutral Aqueous Solutions

Type of Aq. Solution Example(s) Resulting Chemistry or Type of Solution; Calculation Section

strong acid HNO 3 or HCl Completeionization; reaction goes to completion to form H 3 O 18-1
(represented as HX) HXH 2 O88nH 3 OX

strong base NaOH or Completeionization; reaction goes to completion to form OH
18-1
[represented as Ba(OH) 2 MOH88nMOH

MOH or M(OH) 2 ] M(OH)
2 88nM

2 2OH

weak acid CH 3 COOH or Partialionization; HAH 2 O 34 H 3 OA
18-4
(represented as HA) HCN Must solve equilibrium expression involving Kafor the acid

using equilibriumconcentrations: Ka

[H 3

[

O

H



A

][

]

A
]



weak base NH 3 Partialionization; BH 2 O 34 BHOH
18-4
(represented as B) Must solve equilibrium expression involving Kbfor the base,

using equilibriumconcentrations: Kb

[BH

[

]

B

[O

]

H
]



Salt of strong NaNO 3 No hydrolysis—neutral solution 18-7
base& strong acid (salt of NaOH
(represented as MX) and HNO 3 )

Salt of strong base NaCN Hydrolysisof conjugate base (A
) of weak acid:::Fbasicsolution 18-8
& weak acid (salt of NaOH A
H 2 O 34 HAOH

(represented as MA) and HCN)
Solve weak base equilibrium for A
using Kb for A

Ka

K

fo

w

rHA



Salt of weak base NH 4 NO 3 Hydrolysisof conjugate acid (BH) of weak base:::Facidicsolution 18-9
& strong acid (salt of NH 3 BHH 2 O 34 BH 3 O
(represented as and HNO 3 )
Solve weak acid equilibrium for BHusing Ka for BH
Kb

K

fo

w

rB

BHX) 

Salt of weak base&NH 4 CN Hydrolysisof conjugate base (A
) of weak acid:::Fbasicsolution and 18-10
weak acid (salt of NH 3 Hydrolysisof conjugate acid (BH) of weak base:::Facidicsolution.
(represented as BHA) and HCN) This solution can be basic, neutral,or acidic,depending on
which hydrolysis occurs to a greater extent; use Kband Ka
values for the hydrolysis reactionsto tell which ion will be the
dominant factor. (We did not do calculations for this type of salt.)

Weak acid& saltof its CH 3 COOH Salt ionizes completely; MA88nMA
19-1,
conjugate base NaCH 3 COO Mixture of weak acid (HA) and its conjugate base (A
) in 19-2,
(represented as (or the product significant concentrations gives a buffer. 19-3
HA & MA) of the partial Use Henderson–Hasselbalch equation for acid–salt buffer
neutralization in (with initial concentrations or mole ratio):
a titration of a
weak acidwith a pHpKalog

[conju

[a

g

c

a

i

t

d

e

]

base]



strong base

Weak base& saltof NH 3 NH 4 Cl Salt ionizes completely; NH 4 Cl88nNH 4 Cl
19-1,
its conjugate (or the product Mixture of weak base (NH 3 ) and its conjugate acid (NH 4 ) in 19-2,
acid of the partial significant concentrations gives a buffer. 19-3
(represented as neutralization in Use Henderson–Hasselbalch equation for base–salt buffer
B & BHX) a titration of a (with initial concentrations or mole ratio):
weak basewith a
strong acid) pOHpKblog

[conju

[b

g

a

a

s

t

e

e

]

acid]