Ex.12.1a The reactions of ethanoic acid. P.324.

1. Solubility and pH

Substances and tools needed:

1cm³ (roughly) of pure ethanoic acid Full range indicator

A test tube               A pipette full of water    5cm³ of sodium carbonate (Na₂CO₃).

Procedure.

1.     Put 1cm³ of ethanoic acid into a test-tube

2.     Add water and note if they mix various proportions:                                

3.     Add few drops of indicator. Colour:                                                       

4.     Add sodium carbonate solution. Observation:                              

Questions:

What type of intermolecular force helps water and ethanoic acid to mix?

They both have hydrogen bonds present between their atoms and they can form the hydrogen bonds also between each other.

Is ethanoic acid strong enough to displace carbon dioxide from carbonates?

Based on my last experiment if the gas was given off the answer will be yes and vice versa. Answer:                

Equation:

Na₂CO_3(aq) + 2CH₃COOH_(l) 2Na⁺ + 2CH₃COO^- + H₂O + CO₂

K_a for ethanoic acid = 1.7 which is big compared to other carboxylic acids, so ethanoic acid is more dissociated and thus a strong acid.

2. Formation of salts

Substances and tools needed:

10cm³ 0.1M ethanoic acid                 beaker                          Full range indicator (or pH meter)

25cm³ 0.1M NaOH                          Pipette or syringe

Procedure.

1.     Put 10cm³ of ethanoic acid into beaker

2.     Add few drops of indicator

3.     Stir and add 3cm³ of NaOH

4.     Note the pH

5.     Repeat last 2 for 5 times

No. of the go	Measure of the pH / Colour of the indicator
1
2
3
4
Final pH

Explanation:

3. Formation of esters.

Substances and tools needed:

1 cm³ of ethanoic acid           2cm³ of ethanol             3 drops of conc. H₂SO₄             A test-tube

Water bath with HOT WATER         Small beaker     Na₂CO₃

Procedure.

1.     Smell ethanol and ethanoic acid

2.     Add ethanol to ethanoic acid

3.     Add CAREFULLY H₂SO₄

4.     Warm the mixture GENTLY for 5 min.

5.     Smell the mixture. It is like / not like the starting material.

6.     Put the mixture into a beaker filled with Na₂CO₃

7.     Stir and Smell

8.     Smell ethyl ethanoate from a bottle. It smells / smells not like my mixture.

9.     If some esters are available, smell them cautiously

Name of compound	What I see	What I smell

10.   If required look up the table of other esters from a book p.325 and make them in a same way.