Question

1. Identify the substance oxidised and the substance reduced in the

following reaction.

MnO2 +4HCl → MnCl2 + 2H2O + Cl2

2. When the powder of a common metal (M) is heated in an open china dish,

its colour turns black. However, when hydrogen is passed over the hot,

black substance so formed, it regains its original colour.

Based on the above information, answer the following questions.

i) Identify the type of chemical reaction taking place in the two reactions.

ii) Name the metal M.

iii) Write balanced chemical equations for both the reactions.

3. Oil and fat containing food items are flushed with nitrogen. Why?

4. Choose the correct option:

Substances that prevent oxidation are known as:

a) antioxidants

b) antibiotics

c) antigen

d) antiseptics

5. Identify the reducing agent in the following redox reaction:

2PbO +C → 2Pb + CO2

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Answer 1

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ek ek kar ke puchoo

Answer 2

Answer

Explanation:

1. h20 is oxidised

2. 1.) OXIDATION REACTION

2.)METAL IS COPPER

4CU+O2⁻⁻HEAT⇒2CU20(BLACK)

CU2O+H2⇒2CU+H2O

3.Nitrogen is an inert gas which is flushed in food items as it does not react with food items and removes all the oxygen present in food. Oxygen present in food items makes then rancid due to the presence of oils and fats.

4. a)antioxidants

5. PbO->Pb