Ch 14 Salt, Hydrolysis, and Buffers

Relationship btwn K_A and K_B for conjugate acid/base pairs

K_A x K_B = 1×10^-14

Relationship btwn pK_A and pK_B for conjugate acid/base pairs

pK_A + pK_B = 14

There is a(n) ____ relationship between the acidic strength of HA and the ___ strength of A^-

inverse, basic

The relationship between K_A and K_B is ___

inverse

A solution where a weak acid is added to pure water is ___

acidic

A solution where a weak base is added to pure water is ___

basic

Conjugates of strong acids/bases ___ with water

do not

Acidic Salts

salts that yield acidic solutions

For acidic salt: the ___ reacts with water as an acid

cation

Basic salts

salts that yield basic solutions

For basic salts: the ___ reacts with water as a base

anion

Neutral salts

salts that yield neutral solutions

For neutral salt: ____ reacts with water

neither ion

Ions that react with water

Cations of weak bases containing Nitrogen, anions of weak acids

Cations of weak bases have some ___ strength

acidic

Anions of weak acids have some ___ strength

basic

Ions that do not react with water

Cations from strong bases, anions from strong acids

Acid-base buffer contains relatively high and ____ concentrations of a ___

equal, weak conjugate acid/base pair

A buffer works by adding small amounts of ___ or ___

H₃O⁺ , OH^-

H₃O⁺ reacts with ____ component

base

OH^- reacts with ____ component

acid

Addition of a base makes a sln ___

less acidic

Addition of an acid makes a sln ___

less basic

Addition of a neutral salt makes a sln ___

remain the same

For a balanced buffer, [H₃O⁺] = ____, and pH = ____

K_A, pK_A

H-H Equation for buffer pH

pH = pK_A + log (A^- / HA)

Buffer capacity

ability of buffer to maintain the pH with the addition of an acid or base

Raise buffer pH

increase [A^-] and/or decreasing [HA]

Lower buffer pH

decrease [A^-] and/or increase [HA]

Buffer range

pH range over which a buffer can minimize pH change

The closer the [A^-] / [HA] ratio is to ___, the more effective the buffer

1

If one component of the buffer is more than ___ times the other, buffering action is poor

10

Buffers have usable range within _____ unit of the pK_A of the ___ component

+1 pH, acid

Choose weak conjugate pair so pK_A is within _____ of desired pH

1 unit

Solve for [A^-] / [HA] ratio

raise 10 to the value of pH - pK_A

A strong conjugate acid/base pair ___ make a buffer

cannot