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3. Galvanizing the surface of iron article (Galvanization is a process in which a
layer of zinc is coated over iron objects.)

Browning of fruits and vegetables

The change of the colour of the cut fruits is caused due to some chemical reaction.

Open surface of cut fruit and vegetables react with the oxygen of air and oxidised.
This oxidation decreases the nutritional value of the food items.

Reaction between vinegar and baking soda

Vinegar + baking soda  Carbon dioxide + sodium accetate + Water

Different Types of Reactions: -
Displacement Reaction-
Copper sulphate + Iron Iron sulphate + copper
CuSO4 Fe FeSO4 Cu
Decomposition reaction:
Water  Hydrogen + Oxygen
H2O H2 O2
Combination Reaction:
Carbon + Oxygen Carbon dioxide
C O 2 CO2

Crystallisation:

The process in which crystal of pure substances are obtained from their solution is
called crystallisation.

How salt is obtained from the sea?

Sea water contains salt. Salt is obtained by the process of crystallisation.

First sea water is collected in different shallow ponds. The water gets evaporated
under the heat of sun and solid salt is left behind.

Then refining of salt is done by the method of crystallisation.

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