Page 79 - NCERT Science Class 10 English Medium

NaOH
CH COOC H 5 C H OH+CH COONa
2
3
3
5
2
(ii) Reaction with a base: Like mineral acids, ethanoic acid reacts with
a base such as sodium hydroxide to give a salt (sodium ethanoate
or commonly called sodium acetate) and water:
NaOH + CH COOH → CH COONa + H O
3 3 2
How does ethanoic acid react with carbonates and
hydrogencarbonates?
Let us perform an activity to find out.
Activity
Activity 4.9
Activity 4.9
Activity 4.94.9
Activity 4.9
n Set up the apparatus as shown in Chapter 2, Activity 2.5.
n Take a spatula full of sodium carbonate in a test tube and add 2 mL of dilute
ethanoic acid.
n What do you observe?
n Pass the gas produced through freshly prepared lime-water. What do you observe?
n Can the gas produced by the reaction between ethanoic acid and sodium carbonate be
identified by this test?
n Repeat this Activity with sodium hydrogencarbonate instead of sodium carbonate.
(iii) Reaction with carbonates and hydrogencarbonates: Ethanoic acid
reacts with carbonates and hydrogencarbonates to give rise to a
salt, carbon dioxide and water. The salt produced is commonly called
sodium acetate.
2CH COOH + Na CO → 2CH COONa + H O + CO
3 2 3 3 2 2
CH COOH + NaHCO → CH COONa + H O + CO
3 3 3 2 2

Q U E S T I O N S

1. How would you distinguish experimentally between an alcohol and
a carboxylic acid? ?
2. What are oxidising agents?

4.5 SOAPS AND DETERGENTS

Activity
Activity 4.10
Activity 4.104.10
Activity
4.10
Activity 4.10
n Take about 10 mL of water each in two test tubes.
n Add a drop of oil (cooking oil) to both the test tubes
and label them as A and B.
n To test tube B, add a few drops of soap solution.
n Now shake both the test tubes vigourously for
the same period of time.
n Can you see the oil and water layers separately
in both the test tubes immediately after you
stop shaking them?
n Leave the test tubes undisturbed for some time
Figure 4.12
Figure 4.12
Figure 4.12 and observe. Does the oil layer separate out?
Figure 4.12
Figure 4.12
Formation of micelles In which test tube does this happen first?
74 Science

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