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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:

Na2CO3(aq) + 2CH3COOH(l) 2Na+ + 2CH3COO- + H2O + CO2

Ka 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:

Neutralisation reaction CH3COOH(aq) + NaOH (aq) Na+(aq) + CH3COO-(aq) + H2O(l)

 

 

 

 

 

 

 

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.

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