Science Around us

3. CHEMICAL REACTION BASED ON SOLUTION
OF REACTANTS
MILK DECOCTION
SUGAR
COFFEE

4. When we mix two
substances (reactants) in
solution form, the chemical
reaction takes place to form
new substances (products).

5. Example:
Silver Nitrate Sodium Chloride
```````
```````
```````
```
No Reaction

6. ```````
```````
```````
```
```````
```````
```````
```
Silver Nitrate
Silver Nitrate solution
Sodium Chloride
Sodium Chloride solution
Water
Water
White precipitate

7. From this reaction we can
infer that some chemical
reactions proceed only in
solution form and not in
solid form.

8. Chemical reaction based on electricity
Cooking
Lighting
Watching TV
Grinding
Charging Mobiles

9. Electricity can be used to carry
out chemical reaction.
By using electricity many
chemical reactions are taking
place. Mainly in industries
chemical reactions are carried out
using electricity.

10. Water is made up of hydrogen
and oxygen molecules. When
we heat water it converts into
water vapour. It will not split
into hydrogen and oxygen.

11. When electricity is passed through
water containing small amounts of
Sulphuric acid, water decomposes
into hydrogen gas and oxygen gas.
This process is known as Electrolysis.

12. What is Electrolysis?
Electrolysis is a
process by which
electrical energy is
used to produce a
chemical change.

13. What is brine?
Brine is a
Concentrated
solution of
sodium chloride.

14. From the above two reactions,
we infer that some chemical
reactions proceed only by the
passage of electricity. Such
reactions are called
electrochemical reactions.

15. ASSIGNMENT
1. Define electrolysis.
2. What is brine?