Is Dilution the Solution?

Some industries produce acidic wastes.  Do acids become harmless as they are diluted?

How much H2O is needed to neutralize an acid?

Let’s see what happens to 50 mL of 1 M HCl …

Mixing HCl with NaOH (demonstration)

Writing neutralization equations

Assignment

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Characteristics of an acid:

1. It turns blue litmus paper to red

2. It tastes sour. Try drinking lemon juice (citric acid)

3. Corrode metals

4. Reacts with bases to form salts and water

Characteristics of a Base:

1. A bitter taste.

2. It feels slippery. (Soapy Water)

3. It turns red litmus to blue.

4. Reacts with acids to form salts and water

Arrhenius Theory: According to this theory an acid (HA) is a substance that breaks

into H+ ions in an aqueous solution.

A Base (MOH) is a substance that breaks into OH- ions in an aqueous solution.

Bronsted-Lowry Theory: It defines an acid as a proton donor, a base as a proton

acceptor and an acid-base reaction as a proton transfer reaction.

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The stronger the H-A bond, the weaker the acid should be.

The strong bonds are characterized by short bond lengths and high bond dissociation energies.

Example: 50 mL of 0.0155 M HI(aq) is mixed with 75 mL of 0.0106 M KOH(aq). What is the pH of the final solution ?

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