3. What is red ox reaction? Justify your answer with two examples.
4. What is decomposition reaction? Give each example of decomposition
reaction in the presence of Heat, Light and Electricity.
5. what is corrosion? Write the colour of silver, copper and Iron corrosion
6. What is Rancidity? Why Nitrogen gas is kept in chips wrapper.
Answers
Answer:
Explanation:
3. The reaction in which aone reactant gets oxidised and the other gets reduced is called redox reaction.
Example: 2Cu + O2 --------> 2CuO
In the above reaction copper is being oxidised and oxygen is being reduced.
ZnO + C -----------> Zn + CO
In this reaction carbon is being oxidised and zinc is being reduced.
4. The reaction in which one single reactant breaks down to form two or more simpler products is called deopsition reaction.
Reaction in the presence of heat
2FeSO4 ------Δ------> FeSO4 + SO3 + SO2
Reaction in the presence of light
2AgCl -----------> 2Ag + Cl2
Reaction in the presence of electricity
2H2 + O2 ---------------> 2H2O
5. When a metal is attacked by the substances around it such as moisture, acids etc it is said to be corroded. This process is called corrosion.
The colour of corroded silver is black, corroded iron is reddish brown and copper is green.
6. When fats and oils get oxidised they become different in taste and sour as they become rancid. This phenomenon is called rancidity.
Unlike oxygen, nitrogen gas doesn't react with food items and hence prevent oxidaton of food leading to rancidity. So nitrogen gas is flushed in chips packets for keeping it fresher for a long time.