Class 12 Chemistry Mid Term Examination set 2

Class 12 Chemistry Term-End Examination (Medium Standard)

Maximum Marks: 70

Time Allowed: 3 Hours

General Instructions:

• All questions are compulsory.
• The question paper consists of 4 sections:
• Section A: 1-mark questions (MCQs)
• Section B: 2-mark questions (Theory and Numerical)
• Section C: 3-mark questions (Theory and Numerical)
• Section D: 5-mark long-answer questions and comprehension.
• Internal choices are provided for selected questions.
• Use of a scientific calculator is not allowed.
• Diagrams should be neat and labeled appropriately wherever necessary.

Section A: MCQs (1 Mark Each) [Total: 15 Marks]

1. What is the unit of molarity?
   • 1. Moles/liter
   • 2. Grams/liter
   • 3. Molecules/liter
   • 4. Moles/gram
2. Which of the following is a strong acid?
   • 1. HCl
   • 2. CH₃COOH
   • 3. H₂CO₃
   • 4. NH₄OH
3. The chemical formula for water is:
   • 1. H₂O₂
   • 2. H₂O
   • 3. HO₂
   • 4. HOH
4. Which metal is extracted using the electrolytic reduction method?
   • 1. Iron
   • 2. Copper
   • 3. Aluminium
   • 4. Zinc
5. The process of converting a solid directly into vapor is known as:
   • 1. Melting
   • 2. Sublimation
   • 3. Freezing
   • 4. Evaporation
6. The rate of a chemical reaction depends on:
   • 1. Concentration of reactants
   • 2. Concentration of products
   • 3. Both 1 and 2
   • 4. None of these
7. What is the shape of a methane (CH₄) molecule?
   • 1. Linear
   • 2. Trigonal planar
   • 3. Tetrahedral
   • 4. Pyramidal
8. Which one is an example of a colloid?
   • 1. Salt solution
   • 2. Milk
   • 3. Sugar solution
   • 4. Alcohol
9. What happens during oxidation?
   • 1. Gain of electrons
   • 2. Loss of electrons
   • 3. Gain of protons
   • 4. Loss of protons
10. What is the correct pH of a neutral solution?
    • 1. 1
    • 2. 7
    • 3. 14
    • 4. 0
11. Which of the following metals can displace hydrogen from acids?
    • 1. Gold
    • 2. Platinum
    • 3. Zinc
    • 4. Silver
12. The electrolysis of water produces:
    • 1. Hydrogen and oxygen
    • 2. Nitrogen and oxygen
    • 3. Water vapor
    • 4. Carbon dioxide
13. What is the chemical name of common salt?
    • 1. Sodium sulfate
    • 2. Sodium chloride
    • 3. Sodium carbonate
    • 4. Sodium bicarbonate
14. Which of the following is an allotrope of carbon?
    • 1. Graphite
    • 2. Iron
    • 3. Diamond
    • 4. Both 1 and 3
15. The basic unit of an element is:
    • 1. Atom
    • 2. Molecule
    • 3. Electron
    • 4. Proton

Section B: 2 Marks Each [Total: 28 Marks]

16. Define molarity.
    OR
    What is molality?
17. What are isotopes? Give an example.
18. Calculate the mass of NaCl required to prepare 500 mL of a 1 M solution. (Numerical)
19. State the law of conservation of mass with an example.
20. What are covalent bonds? Give an example.
    OR
    Define ionic bonds and give an example.
21. Write the balanced equation for the reaction between hydrochloric acid and sodium hydroxide.
22. Define valency. What is the valency of oxygen?
23. What is electrolysis? Give an example.
24. Calculate the number of moles in 88 g of CO₂. (Numerical)
    OR
    Define the mole concept.
25. Write the chemical formula of calcium carbonate and calcium chloride.
26. What are acids? Give two examples.
    OR
    What are bases? Give two examples.
27. Explain the term sublimation with an example.
28. Write the equation for the electrolysis of water.
    OR
    Write the equation for the decomposition of hydrogen peroxide.
29. What are catalysts? Give an example.

Section C: 3 Marks Each [Total: 12 Marks]

30. State Dalton’s atomic theory and its significance.
31. Explain the process of rusting.
    OR
    How can rusting be prevented?
32. Define exothermic and endothermic reactions with examples.
33. Differentiate between metals and non-metals based on their properties.

Section D: 5 Marks Each [Total: 10 Marks]

34. Explain the extraction of aluminium from its ore using the electrolytic process.
    OR
    Describe the extraction of iron from its ore using the blast furnace.
35. Explain the working of a simple voltaic cell with a neat labeled diagram.
    OR
    Describe the electrolysis of copper sulfate solution.

Comprehension [Total: 5 Marks]

Read the following passage and answer the questions that follow:

"Water is an essential substance for all living organisms. It plays a vital role in biological processes and is considered a universal solvent. Water exists in three states: solid, liquid, and gas. The properties of water are unique due to its polar nature and hydrogen bonding. These properties are responsible for its high boiling and melting points, surface tension, and capillary action."

1. What are the three states of water? (1 mark)
2. Why is water called a universal solvent? (1 mark)
3. What property of water is responsible for its high boiling point? (1 mark)
4. What is capillary action? (1 mark)
5. What role does water play in biological processes? (1 mark)