Here you will find NCERT Activity 3.9 Class 10 Science Explanation that belongs to Chapter 3 Metals and Non-metals. After reading Solutions of chapter 3 Metals and Non-metals, you will be able to understand activity 3.9.
NCERT Activity 3.9 Class 10 Science Explanation
Caution: The following activities need the teacher’s
assistance. It would be better if students wear eye protection.
Activity 3.9 Class 10 Science
· Hold
any of the samples taken above with a pair of tongs and try burning over a
flame. Repeat with the other metal samples.
· Collect
the product is formed.
· Let
the products and the metal surface cool down.
· Which
metals burn easily?
· What
flame colour did you observe when the metal burnt?
· How
does the metal surface appear after burning?
· Arrange
the metals in the decreasing order of their reactivity towards oxygen.
· Are
the products soluble in water?
Observation
: (i) Potassium, Sodium and magnesium burn easily.
2Mg(s) + O2 2MgO(s)
MgO(s) + H2O(l) Mg(OH)2
(aq)
(ii) Copper and aluminium do not burn but on heating in air form black copper (II) oxide and white aluminium oxide (Al2O3) respectively.
2Cu +O2 → heat 2CuO
Cupric oxide
4Al + 3O2(g) 2AI2O3(s)
(iii) Copper and aluminium metal oxides are insoluble
in water. But, alkali metal oxides (Na2O, K2O)
dissolve in water to produce alkalis.
The order of reactivity with oxygen is:
K > Na > Mg > AI > Cu
Conclusion :
(i) The oxide of metals is basic in nature and it is dissolved in water to form
alkalies.
(ii) At ordinary temperature the surface of metals,
such as aluminium, iron, zinc and lead etc. are covered with a thin layer of
the oxide which reduces their further reactivity towards oxygen.
Related Topics -
1. Next activity - Activity 3.10
2. Previous activity -Activity 3.8
3. Solution of Chapter 3 Metals and Non-metals
5. Extra Questions of Chapter 3
6. Solutions of Class 10 Science all chapters
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