Observe the following figure and answer the questions:
1) the lead of pencil writes on the paper .why?
2) assemble the appartus as shown in the figure,. Start the electric current in the circuit. Observe . What did you find?
3) take some water in a test tube . Take some kerosene in another test tube . Put lead dust in both the test tubes . What did you find ?
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1. Lead is usually made of carbon, graphite which usually leaves a mark on paper. A pencil is made from clay mixed with graphite in a wooden casing.
While writing the particles of graphite and clay come off easily and get deposited on paper due to the movement of hand that creates friction.
3. In normal conditions lead will not react to water. But, when lead gets in touch with moist air the reactivity with water will increase. A small lead oxide (PbO) layer will form at the surface. When oxygen and water both are there, then metallic lead gets converted to lead hydroxide (Pb(OH)2):
2Pb(s)+ O2(g) + 2H2O(l) -> 2 Pb(OH)2(s)
There is no reaction with Kerosene until the mixture is heated. This is because kerosene is a hydrocarbon.
While writing the particles of graphite and clay come off easily and get deposited on paper due to the movement of hand that creates friction.
3. In normal conditions lead will not react to water. But, when lead gets in touch with moist air the reactivity with water will increase. A small lead oxide (PbO) layer will form at the surface. When oxygen and water both are there, then metallic lead gets converted to lead hydroxide (Pb(OH)2):
2Pb(s)+ O2(g) + 2H2O(l) -> 2 Pb(OH)2(s)
There is no reaction with Kerosene until the mixture is heated. This is because kerosene is a hydrocarbon.
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