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Q2 In the reaction PbS+4H 2O 2PbSO 4+4H 2O 1

i) Which substance is reduced?

ii) Which substance is oxidized?

Q3 Is oxidation an exothermic or an endothermic reaction? Justify your 1
answer.

Q4 Mg+CuO MgO+Cu 1

Classify the above reaction into two types.

Q5 When a strip of reddish brown metal X is placed in a colourless salt 1
solution YNO 3, a shiny grey deposit is found on metal X along with
formation of blue coloured solution.

i) Identify X ii) Name the salt YNO 3

Concept_Corrosion

Q1. What is the special name given to corrosion of iron? Name any two 1
objects/structures which are gradually damaged by the corrosion of
iron.

Q2 Which type of chemical reactions is involved in corrosion of iron metal? 1

Q3 Define corrosion. 1

Q4 Why is corrosion not acceptable? 1

Q5 State an example of corrosion of a metal that produces positive effect. 1

Concept_Rancidity

Q1. Which gas is flushed in the chips packets and why? 1

Q2 Define rancidity. 1

Q3 Which type of chemical reaction is responsible for causing rancidity? 1

Q4 State any two ways of preventing rancidity. 1

Q5 Give any two examples of rancidity. 1

Q6. How will you identify the rancid food? 1

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