Class 10 Metals Non-Metals Chemical Properties MCQ Set 4 | NCERT CBSE JKBOSE

 

SET 4: Redox Reactions and Everyday Chemistry

50 Multiple Choice Questions

Introduction: This advanced set explores redox reactions in detail, including oxidizing and reducing agents, everyday examples of oxidation, and the chemistry behind corrosion and food preservation. Ideal for Class 10 NCERT, JKBOSE, and CBSE students.

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📌 Quiz: SCIENCE

📚 Subject: CHEMISTRY

🏫 Class: CLASS 10

📖 Chapter: Chemical Reactions and Equations-D

📝 Questions: 50

📘 SCIENCE

CHEMISTRY | Chemical Reactions and Equations-D

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Q1. What happens when copper powder is heated in air?

A. It melts

B. It turns white

C. Its surface gets coated with black copper(II) oxide

D. It evaporates

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Q2. In the reaction 2Cu + O₂ → 2CuO, what happens to the copper?

A. It is reduced

B. It is oxidised

C. It is displaced

D. It is decomposed

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Q3. What change is observed when hydrogen gas is passed over heated copper(II) oxide?

A. The black coating turns blue

B. The black coating turns brown and copper is obtained

C. A white precipitate forms

D. The coating turns green

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Q4. In the reaction CuO + H₂ → Cu + H₂O, what happens to copper(II) oxide?

A. It is oxidised

B. It is reduced

C. It is decomposed

D. It is displaced

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Q5. What is a reaction called where one substance is oxidised and another is reduced?

A. Displacement reaction

B. Combination reaction

C. Oxidation-reduction or redox reaction

D. Double displacement reaction

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Q6. In the reaction ZnO + C → Zn + CO, which substance is oxidised?

A. Zinc oxide (ZnO)

B. Carbon (C)

C. Zinc (Zn)

D. Carbon monoxide (CO)

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Q7. In the reaction ZnO + C → Zn + CO, which substance is reduced?

A. Carbon (C)

B. Zinc (Zn)

C. Zinc oxide (ZnO)

D. Carbon monoxide (CO)

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Q8. In the reaction MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂, which substance is reduced?

A. Hydrochloric acid (HCl)

B. Manganese dioxide (MnO₂)

C. Manganese chloride (MnCl₂)

D. Chlorine (Cl₂)

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Q9. In the reaction MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂, which substance is oxidised?

A. Water (H₂O)

B. Manganese dioxide (MnO₂)

C. Hydrochloric acid (HCl)

D. Manganese chloride (MnCl₂)

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Q10. A substance is oxidised if it:

A. Gains oxygen or loses hydrogen

B. Loses oxygen or gains hydrogen

C. Loses electrons only

D. Gains electrons only

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Q11. A substance is reduced if it:

A. Gains oxygen or loses hydrogen

B. Loses oxygen or gains hydrogen

C. Gains electrons only

D. Loses electrons only

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Q12. When magnesium burns in air to form magnesium oxide, what happens to magnesium?

A. It is reduced

B. It is oxidised

C. It is displaced

D. It is decomposed

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Q13. What is the common term for the reddish-brown coating formed on iron when left exposed?

A. Tarnishing

B. Galvanisation

C. Rusting

D. Rancidity

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Q14. What is the general term for the process where a metal is attacked by substances like moisture and acids?

A. Reduction

B. Oxidation

C. Corrosion

D. Displacement

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Q15. What are examples of corrosion on other metals besides iron?

A. Black coating on silver and green coating on copper

B. White coating on zinc and blue coating on aluminium

C. Red coating on gold and yellow coating on lead

D. Brown coating on magnesium and grey coating on sodium

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Q16. What is a major negative effect of corrosion?

A. It makes metals stronger

B. It causes damage to metal objects like bridges and ships

C. It prevents metals from reacting

D. It improves the appearance of metals

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Q17. What happens when fats and oils in food are oxidised?

A. They become more nutritious

B. They become rancid, changing their smell and taste

C. They turn into proteins

D. They become sweeter

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Q18. What are substances called that are added to food to prevent oxidation?

A. Preservatives

B. Antioxidants

C. Catalysts

D. Reducing agents

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Q19. How does keeping food in airtight containers help?

A. It makes food cook faster

B. It slows down oxidation

C. It increases the fat content

D. It speeds up bacterial growth

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Q20. Why do chips manufacturers flush bags of chips with nitrogen gas?

A. To make the chips heavier

B. To add flavour

C. To prevent the chips from getting oxidised

D. To change their colour

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Q21. In the redox reaction CuO + H₂ → Cu + H₂O, which substance is the reducing agent?

A. Copper oxide (CuO)

B. Water (H₂O)

C. Hydrogen (H₂)

D. Copper (Cu)

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Q22. In the redox reaction CuO + H₂ → Cu + H₂O, which substance is the oxidising agent?

A. Hydrogen (H₂)

B. Water (H₂O)

C. Copper (Cu)

D. Copper oxide (CuO)

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Q23. What is the colour change when hydrogen reduces hot copper(II) oxide?

A. White to grey

B. Black to brown

C. Blue to green

D. Red to black

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Q24. Which of the following is NOT a characteristic of a redox reaction?

A. Involves gain of oxygen

B. Involves loss of oxygen

C. Only one substance changes

D. Both oxidation and reduction occur

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Q25. The process of rusting of iron involves which type of reaction?

A. Displacement

B. Combination

C. Oxidation

D. Decomposition

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Q26. What is the main economic impact of corrosion?

A. It creates jobs

B. An enormous amount of money is spent to replace damaged iron

C. It makes metals more valuable

D. It has no economic impact

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Q27. What gas is used to flush chip bags to prevent rancidity?

A. Oxygen

B. Carbon dioxide

C. Hydrogen

D. Nitrogen

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Q28. Which of these is a method to prevent rancidity?

A. Adding water

B. Keeping food exposed to air

C. Adding antioxidants

D. Heating food continuously

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Q29. In the reaction where copper gains oxygen, the copper is said to be:

A. Reduced

B. Oxidised

C. Decomposed

D. Precipitated

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Q30. What is the term for the reaction that is the opposite of oxidation?

A. Combustion

B. Reduction

C. Decomposition

D. Displacement

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Q31. Which of the following processes is an example of oxidation in everyday life?

A. Cutting an apple and it turns brown

B. Melting of butter

C. Freezing of water

D. Mixing salt in water

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Q32. What is the visual sign that a redox reaction has occurred in the copper heating experiment?

A. Formation of a gas

B. Change in colour of the metal

C. Formation of a precipitate

D. Change in temperature

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Q33. HCl is oxidised to Cl₂ because it:

A. Gains oxygen

B. Loses hydrogen

C. Loses oxygen

D. Gains hydrogen

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Q34. What is the primary cause of the rancidity of fatty foods?

A. Reduction reaction

B. Oxidation reaction

C. Double displacement

D. Decomposition by heat

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Q35. Why is corrosion considered a redox process?

A. Because it involves only reduction

B. Because it involves only decomposition

C. Because it involves both oxidation of the metal and reduction of oxygen

D. Because it involves displacement

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Q36. In the reaction CuO + H₂ → Cu + H₂O, hydrogen:

A. Is oxidised to water

B. Is reduced to water

C. Is decomposed

D. Acts as an oxidising agent

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Q37. What is the common element involved in both corrosion and rancidity?

A. Nitrogen

B. Hydrogen

C. Oxygen

D. Carbon

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Q38. What is the main purpose of the reaction where hydrogen gas is passed over heated copper oxide?

A. To produce water

B. To demonstrate a displacement reaction

C. To demonstrate reduction of a metal oxide

D. To demonstrate decomposition

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Q39. Which of the following is a consequence of rancidity?

A. Improved food texture

B. Change in smell and taste of food

C. Increase in nutritional value

D. Food becomes softer

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Q40. What is the primary reason that stainless steel resists rusting better than ordinary iron?

A. Stainless steel is harder

B. Stainless steel contains chromium which forms a protective oxide layer

C. Stainless steel is heavier

D. Stainless steel does not contain iron

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Q41. The green coating on copper is a result of:

A. Reduction

B. Corrosion

C. Rancidity

D. Displacement

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Q42. In a redox reaction, the total amount of oxygen lost by one substance is:

A. Equal to the oxygen gained by another

B. More than the oxygen gained

C. Less than the oxygen gained

D. Unrelated to the oxygen gained

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Q43. What common household practice can slow down food spoilage due to rancidity?

A. Storing in open containers

B. Refrigeration

C. Adding more oil

D. Storing in airtight containers

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Q44. What is the chemical nature of the "black substance" formed on heating copper?

A. Copper carbonate

B. Copper oxide

C. Copper chloride

D. Copper sulphate

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Q45. The conversion of ZnO to Zn in the reaction with carbon is an example of:

A. Oxidation of zinc

B. Reduction of zinc oxide

C. Reduction of carbon

D. Displacement of oxygen

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Q46. Which of the following is a problem caused by oxidation reactions?

A. Formation of alloys

B. Corrosion of metals

C. Production of salts

D. Neutralisation

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Q47. In the context of food preservation, flushing with nitrogen is effective because nitrogen:

A. Is an oxidising agent

B. Is a reducing agent

C. Is chemically unreactive (inert)

D. Adds flavour

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Q48. The reaction MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂ demonstrates that oxidation can involve:

A. Only gain of oxygen

B. Only loss of hydrogen

C. Both gain of oxygen and loss of hydrogen

D. Neither gain of oxygen nor loss of hydrogen

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Q49. What is the scientific term for the "reverse reaction" mentioned when hydrogen is passed over CuO?

A. Displacement

B. Decomposition

C. Redox

D. Reduction

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Q50. The fundamental idea behind the concept of redox reactions is the:

A. Exchange of ions

B. Transfer of oxygen or hydrogen between substances

C. Formation of a precipitate

D. Absorption of heat

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