2023 Chemistry

1. What happens to the position of equilibrium, if a reversible exothermic reaction is subjected to a decrease in temperature?

• A. The position of equilibrium shifts to the left
• B. The position of equilibrium shifts to the right.
• C. The position of equilibrium remains unchanged
• D. The reaction stops

2. Which noble gas is radioactive and is produced as a decay product of uranium and thorium?

• A. Argon
• B. Krypton
• C. Radon
• D. Neon

3. Which of the following reactions would be expected to have the highest entropy change?

• A. Liquid → Gas
• B. Solid → Liquid
• C. Gas → Liquid
• D. Gas → Solid

4. What is the sum of the oxidation numbers in a neutral compound?

• A. +2
• B. -1
• C. 0
• D. +1

5. According to the kinetic theory of gases, the pressure exerted by a gas is due to

• A. The vibrations of gas particles.
• B. The weight of the gas particles
• C. The attractive forces between gas particles
• D. The collisions of gas particles with the container walls

6. What is eutrophication?

• A. The release of harmful chemicals into water bodies
• B. The excessive growth of algae due to nutrient enrichment
• C. The presence of heavy metals in water
• D. The formation of oil slicks on water surfaces

7. What is the name of the process by which ammonia is produced on an industrial scale?

• A. Nitrogenation
• B. Ammoniation
• C. Nitrification
• D. Haber process

8. Who proposed the planetary model of the atom with electrons orbiting the nucleus?

• A. Erwin Schrödinger
• B. Ernest Rutherford
• C. Niels Bohr
• D. J.J. Thomson

9. Which of the following is an example of an endothermic reaction?

• A. Combustion of propane (C₃H₈) to produce carbon dioxide (CO₂) and water (H₂O).
• B. Burning of methane (CH₄) in the presence of oxygen
• C. Formation of table salt (NaCl) from sodium (Na) and chlorine (Cl22).
• D. Decomposition of hydrogen peroxide (H₂O₂) into water (H₂O) and oxygen (O₂).

10. What happens to the value of the equilibrium constant (K_c) for a reaction if the reaction is reversed?

• A. It becomes zero
• B. It becomes negative
• C. It remains the same
• D. It becomes the reciprocal of the original value

11. What is the chemical structure of soap and detergent molecules?

• A. Hydrophilic head and hydrophobic tail
• B. Hydrophilic head and hydrophilic tail
• C. Hydrophobic head and hydrophobic tail
• D. Hydrophilic tail and hydrophobic head

12. What is the solubility product constant (K_sp) used for?

• A. To measure the total mass of a solute that can dissolve in a solvent
• B. To determine the concentration of a solute in a saturated solution
• C. To calculate the solubility of a solute in a given solvent
• D. To compare the solubilities of different solutes in the same solvent

13. Which trace gas in the atmosphere plays a significant role in the greenhouse effect?

• A. Oxygen
• B. Argon
• C. Carbon dioxide
• D. Nitrogen

14. Which of the following methods can be used to remove temporary hardness from water?

• A. Boiling
• B. Filtration
• C. sedimentation
• D. Chlorination

15. What is Faraday’s constant?

• A. 6.022 x 10²³ mol⁻¹
• B. 3.00 x 10⁸ m/s
• C. 9.81 m/s²
• D. 96,485 C/mol

16. A gas occupies a volume of 1.5 liters at a pressure of 2 atmospheres. If the pressure is increased to 4 atmospheres while the temperature remains constant, what will be the new volume of the gas?

• A. 6 liters
• B. 1.5 liters
• C. 0.75 liters
• D. 3 liters

17. Stainless steel is an alloy made up of

• A. Iron and zinc
• B. Copper and tin
• C. Iron and chromium
• D. Iron and carbon

18. What is the state of matter in which particles are widely spaced and move freely with high kinetic energy?

• A. Liquid
• B. Solid
• C. Plasma
• D. Gas

19. Identify the reducing agent in the following reaction:
    Zn + CuSO₄→ ZnSO₄+ Cu

• A. Cu
• B. Zn
• C. ZnSO₄
• D. CuSO₄

20. Balance the following redox reaction:
    Fe₂O₃+ CO → Fe + CO₂

• A. Fe₂O₃ + CO → 2Fe + 2CO₂
• B. 2Fe₂O₃ + 3CO → 4Fe + 3CO₂
• C. Fe₂O₃ + 2CO → 2Fe + 2CO₂
• D. Fe₂O₃ + 3CO → 2Fe + 3CO₂

21. What is the trend for ionization energy across a period in the periodic table?

• A. Increases from left to right.
• B. Remains constant
• C. Varies randomly
• D. Decreases from left to right

22. Which type of chemical combination involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions?

• A. Ionic bonding
• B. Hydrogen bonding
• C. Covalent bonding
• D. Metallic bonding

23. Which of the following alkanes has a straight-chain structure?

• A. Cyclopentane (C₅H₁₀)
• B. Isobutane (C₄H₁₀)
• C. 2 – methyl propane (C₄H₁₀)
• D. Pentane (C₅H₁₂)

24. What is the product of the electrolysis of aqueous sodium chloride (NaCl) using inert electrodes?

• A. Hydrogen gas at the cathode and chlorine gas at the anode
• B. Hydrogen gas at the cathode and oxygen gas at the anode
• C. Sodium metal at the cathode and chlorine gas at the anode
• D. Sodium metal at the cathode and oxygen gas at the anode

25. When an acidic solution is diluted, what happens to its pH?

• A. It depends on the specific acid
• B. It decreases
• C. It remains the same
• D. It increases

26. Which of the following factors does NOT affect the rate of a chemical reaction?

• A. Concentration of reactants
• B. Presence of a catalyst
• C. Molecular weight of products
• D. Temperature

27. Which organic compound is responsible for the characteristic aroma of fruits?

• A. Alkane
• B. Alkyne
• C. Ester
• D. Amine

28. What is the molar mass of water (H₂O)?

• A. 18 g/mol
• B. 22 g/mol
• C. 16 g/mol
• D. 12 g/mol

29. What is the chemical formula of rust, which is formed on the surface of iron in the presence of oxygen and moisture?

• A. Fe₃O₄
• B. FeO
• C. Fe(OH)₃
• D. Fe₂O₃

30. How many pi (ππ) bonds are there in an alkene with six carbon atoms?

• A. 1
• B. 6
• C. 5
• D. 3

31. What is the principal ore of iron, from which iron is extracted?

• A. Calcite
• B. Bauxite
• C. Magnetite
• D. Hematite

32. Which group does calcium belong to in the periodic table?

• A. Alkaline earth metals
• B. Halogens
• C. Alkali metals
• D. Noble gases

33. Which of the following is a primary constituent of crude oil?

• A. Pentane
• B. Ethanol
• C. Heptane
• D. Methane

34. What is the main source of carbon monoxide (CO) in urban areas?

• A. Volcanic eruptions
• B. Vehicle emissions
• C. Forest fires
• D. Industrial processes

35. What is the empirical formula of a compound containing 40.00% carbon, 6.67% hydrogen, and 53.33% oxygen by mass?

• A. C₄H₈O₄
• B. CH₂O
• C. C₂H₄O₂
• D. C₃H₆O₃

36. Which separation technique is used to separate different pigments in a mixture based on their affinity for a stationary phase and a mobile phase?

• A. Chromatography
• B. Filtration
• C. Decantation
• D. Distillation

37. What is the common name for ethanoic acid?

• A. Acetic acid
• B. Butyric acid
• C. Propionic acid
• D. Formic acid

38. What type of reaction is involved in the formation of alkanols from alkenes?

• A. Elimination reaction
• B. Redox reaction
• C. Substitution reaction
• D. Addition reaction

39. What is the mass percentage of carbon (C) in methane (CH₄)? (The molar mass of carbon is approximately 12 g/mol.)

• A. 25%
• B. 12%
• C. 75%
• D. 50%

40. Which of the following is a common property of non-metals?

• A. Exist as solids at room temperature
• B. Tend to gain electrons in chemical reactions
• C. High thermal conductivity
• D. Readily form cations in chemical reactions

41. What is the symbol used to represent an alpha particle?

• A. α
• B. γ
• C. δ
• D. β

42. When a substance is oxidized, it

• A. Loses electrons
• B. Gains oxygen atoms
• C. Gains electrons
• D. Loses protons (H+ ions)

43. A blue litmus paper turns red when dipped into a solution. What does this indicate about the solution?

• A. The solution is basic
• B. The solution is neutral
• C. The solution is acidic
• D. The litmus paper is faulty

44. Which of the following compounds is an example of an electrovalent bond?

• A. NaCl (sodium chloride)
• B. CO₂ (carbon dioxide)
• C. H₂O (water)
• D. CH₄ (methane)

45. If gas A has a molar mass of 32 g/mol and gas B has a molar mass of 64 g/mol, what is the ratio of their diffusion rates?

• A. 2:1
• B. 1:2
• C. 1:1
• D. 1:4

46. The contact process is used for the industrial production of

• A. sulfuric acid (H₂SO₄)
• B. Hydrochloric acid (HCl)
• C. Sodium hydroxide (NaOH)
• D. Calcium oxide (CaO)

47. Which of the following is a unique property of water compared to other liquids?

• A. It is a poor solvent
• B. It does not evaporate
• C. It expands when freezing
• D. It has a low heat capacity

48. Sodium reacts vigorously with water to produce

• A. Sodium chloride (NaCl) and oxygen gas (O₂)
• B. Sodium nitrate (NaNO₃) and water (H₂O)
• C. Sodium hydroxide (NaOH) and hydrogen gas (H₂)
• D. Sodium oxide (Na₂O) and hydrogen gas (H₂)

49. At room temperature and standard pressure, chlorine gas is in which state of matter?

• A. Plasma
• B. Solid
• C. Liquid
• D. Gas

50. What is the molecular geometry of a molecule with three bonding pairs and no lone pairs around the central atom?

• A. Tetrahedral
• B. Trigonal planar
• C. Linear
• D. Octahedral