Solutions Sheet For Weak Acids Or Weak Bases (Page 2 of 2) in pdf

Solutions Sheet For Weak Acids Or Weak Bases Page 2

Ways to get a buffer system:

• Mixing a weak acid and its salt, e.g., HCN and NaCN

• Mixing a weak base and its salt, e.g., NH 3 and NH 4 Cl

• Titration or mixing problems where a weak acid and a strong base are mixed at the point

where there is some weak acid (left) and some of its salt (newly formed) are present.

• Titration or mixing problems where a weak base and a strong acid are mixed at the point

where there is some weak base (left) and some of its salt (newly formed) are present.

Equivalence Point:

When an equivalent amount of an acid and a base are added to each other causing

neutralization.

•

For a strong acid and a strong base, all that is formed is a salt that will not hydrolyze, i.e.,

neither the anion or the cation wants to steal or give an H + .

For a weak acid and strong base, the salt anion (A - ) undergoes hydrolysis (steals some H +

•

from H 2 O) giving a basic solution.

For a weak base and strong acid, the salt anion (BH + ) undergoes hydrolysis (gives up

•

some H + ) giving an acidic solution.

Solutions Sheet For Weak Acids Or Weak Bases Page 2