MCQOPTIONS
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MCQOPTIONS
This section includes 76 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The dissociation constant of H2O at 25° C is |
| A. | 10-14 M |
| B. | 1014 M |
| C. | 10-7 M |
| D. | 107 M |
| Answer» B. 1014 M | |
| 2. |
Which among the following statements is true about the following chemical reaction?3Fe(s) + 4H₂O → Fe₃O₄ (s) + 4H₂ |
| A. | Iron metal is getting reduced |
| B. | Water is acting as a reducing agent |
| C. | Water is acting as an oxidizing agent |
| D. | Water is getting oxidized |
| Answer» D. Water is getting oxidized | |
| 3. |
If pH of solution of NaOH is 12.0 the pH of H₂SO₄ solution of same molarity will be? |
| A. | 2.0 |
| B. | 12.0 |
| C. | 1.7 |
| D. | 10.0387 |
| Answer» D. 10.0387 | |
| 4. |
Calculate the pKₐ of lactic acid, given that when the concentration of lactic acid is 0.010M and the concentration of lactate is 0.087M, the pH is 4.80. |
| A. | 4.0 |
| B. | 3.9 |
| C. | 3.3 |
| D. | 4.1 |
| Answer» C. 3.3 | |
| 5. |
Which of the following does not react with water? |
| A. | Barium |
| B. | Calcium |
| C. | Beryllium |
| D. | Strontium |
| Answer» D. Strontium | |
| 6. |
Identify the products formed in the following reaction.CH₃COOCH₃ + H₂O → A + B |
| A. | CH₃COOH and CH₃OH |
| B. | CH₃COOOH and CH₄ |
| C. | CO₂ and C₂H₆ |
| D. | No reaction |
| Answer» B. CH₃COOOH and CH₄ | |
| 7. |
Which can act as buffer? |
| A. | NH₄Cl + HCl |
| B. | CH₃COOH + H₂CO₃ |
| C. | 40ml of 0.1M NaCN + 20ml of 0.1M HCN |
| D. | NaCl + NaOH |
| Answer» D. NaCl + NaOH | |
| 8. |
Assertion A: pH of a buffer solution solution does not change on dilution.Reason R: On dilution the ration of concentration of salt and acid (or base) remains unchanged. |
| A. | A and R are true, R is the correct explanation of A |
| B. | A and R are true, R is not correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. A and R are true, R is not correct explanation of A | |
| 9. |
Hydrolysis reactions are catalyzed by enzymes called ___________ |
| A. | Oxidoreductase |
| B. | Ligase |
| C. | Hydrolase |
| D. | Isomerase |
| Answer» D. Isomerase | |
| 10. |
Calculate the pH of a mixture of 0.10M acetic acid and 0.20M sodium acetate. The pKₐ of acetic acid is 4.76. |
| A. | 5.1 |
| B. | 4.1 |
| C. | 6.1 |
| D. | 7.1 |
| Answer» B. 4.1 | |
| 11. |
Which of the following is the correct equation? |
| A. | CO₂ + H₂O → H₂CO₃ |
| B. | CO₂ + H₂O → HCO₃ |
| C. | CO₂ + H₂O → H₃CO₃ |
| D. | CO₂ + H₂O → H₂CO₂ |
| Answer» B. CO₂ + H₂O → HCO₃ | |
| 12. |
What does it mean when we say that water acts as a “heat buffer”? |
| A. | It keeps the temperature of an organism relatively constant as the temperature of the surroundings fluctuates |
| B. | It increases the temperature of an organism as the temperature of the surroundings increases |
| C. | It decreases the temperature of an organism as the temperature of the surroundings increases |
| D. | It increases the temperature of an organism as the temperature of the surroundings decreases |
| Answer» B. It increases the temperature of an organism as the temperature of the surroundings increases | |
| 13. |
Consider the following reaction, in the presence of light2H₂O + 2X → O₂ + 2XH₂Which of the following statements is true? |
| A. | X is electron-accepting specie |
| B. | X is electron-donating specie |
| C. | Water is an electron acceptor |
| D. | Water neither donates nor accepts any electron |
| Answer» B. X is electron-donating specie | |
| 14. |
The buffer capacity is equal to __________ |
| A. | Δn / ΔpH |
| B. | pH / Δn |
| C. | ± 1pKₐ |
| D. | ± 2pKₐ |
| Answer» B. pH / Δn | |
| 15. |
Which of the following mixture in aqueous solution of equimolar concentration acts as a buffer solution? |
| A. | HNO₃ + NaOH |
| B. | H₂SO₄ + KOH |
| C. | NH₄OH(excess) + HCl |
| D. | CH₃COOH + NaOH(excess) |
| Answer» D. CH₃COOH + NaOH(excess) | |
| 16. |
Calculate the ratio of the concentrations of acetate and acetic acid required in a buffer system of pH 5.30. |
| A. | 3.2 |
| B. | 3.3 |
| C. | 3.4 |
| D. | 3.5 |
| Answer» E. | |
| 17. |
Which of the following is not a condensation reaction? |
| A. | ADP + inorganic phosphate → ATP + H₂O |
| B. | R-OH + inorganic phosphate → phosphate ester + H₂O |
| C. | R-COOH + inorganic phosphate → Acyl phosphate + H₂O |
| D. | 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6CO₂ |
| Answer» E. | |
| 18. |
Tertiary conformation of proteins is maintained by 3 types of bonds namely ionic, hydrogen and ____________ |
| A. | Sulfide |
| B. | Disulfide |
| C. | Covalent |
| D. | Peptide |
| Answer» C. Covalent | |
| 19. |
What trend does the reactivity of group II elements follow with water? |
| A. | Increases down the group |
| B. | Decreases down the group |
| C. | Does not follow any particular trend |
| D. | No reaction |
| Answer» B. Decreases down the group | |
| 20. |
Buffer capacity is maximum when __________ |
| A. | One mole of NH₄Cl is added to two moles of NH₄OH |
| B. | One mole of NH₄Cl is added to one moles of NH₄OH |
| C. | One mole of NH₄Cl is added to one mole of NaOH |
| D. | One mole of NaCl is added to one mole of NaOH |
| Answer» C. One mole of NH₄Cl is added to one mole of NaOH | |
| 21. |
1M NaCl and 1M HCl are present in an aqueous solution. What is the solution? |
| A. | Not a buffer solution with pH < 7 |
| B. | Not a buffer solution with pH > 7 |
| C. | A buffer solution with pH < 7 |
| D. | A buffer solution with pH > 7 |
| Answer» B. Not a buffer solution with pH > 7 | |
| 22. |
Which of the following is a hypotonic solution? |
| A. | 10% dextrose in water |
| B. | 0.45% sodium chloride |
| C. | 5% dextrose in 0.9% sodium chloride |
| D. | Oceans |
| Answer» C. 5% dextrose in 0.9% sodium chloride | |
| 23. |
1M NaCl and 1M HCl are present in an aqueous solution. The solution is ____________ |
| A. | Not a buffer solution with pH < 7 |
| B. | Not a buffer solution with pH > 7 |
| C. | A buffer solution with pH < 7 |
| D. | A buffer solution with pH > 7 |
| Answer» B. Not a buffer solution with pH > 7 | |
| 24. |
The bond dissociation energy of hydrogen bonds in a water molecule is ______________ |
| A. | 470 kJ/mole |
| B. | 470 J/mole |
| C. | 23 kJ/mole |
| D. | 23 J/mole |
| Answer» D. 23 J/mole | |
| 25. |
Which of the following is an isotonic solution? |
| A. | 0.9% sodium chloride |
| B. | 0.45% sodium chloride |
| C. | Oceans |
| D. | 10% dextrose in water |
| Answer» B. 0.45% sodium chloride | |
| 26. |
The bond dissociation energy of O-H bond in a water molecule is _____________ |
| A. | 23 kJ/mole |
| B. | 470 kJ/mole |
| C. | 470 J/mole |
| D. | 23 J/mole |
| Answer» C. 470 J/mole | |
| 27. |
Which of the following acids has the lowest pKₐ value? |
| A. | Acetic acid |
| B. | Sulphuric acid |
| C. | Dil.HCl |
| D. | Oxalic acid |
| Answer» C. Dil.HCl | |
| 28. |
What is the concentration of OH⁻ in a solution with a H⁺ concentration of 1.3×10⁻⁴ M? |
| A. | 7.7×10⁻¹⁰ M |
| B. | 7.7×10⁻⁹ M |
| C. | 7.7×10⁻¹¹ M |
| D. | 7.7×10⁻¹² M |
| Answer» D. 7.7×10⁻¹² M | |
| 29. |
Which of the following bases has the highest pKₐ value? |
| A. | NaOH |
| B. | NaNO₃ |
| C. | KNO₃ |
| D. | KCl |
| Answer» B. NaNO₃ | |
| 30. |
K1 and K2 for oxalic acid are 6.5×10⁻² and 6.1×10⁻⁵ respectively. What will be the [OH⁻] in a 0.01M solution of sodium oxalate? |
| A. | 9.6×10⁻⁶ |
| B. | 1.4×10⁻¹ |
| C. | 1.2×10⁻⁶ |
| D. | 1.3×10⁻⁸ |
| Answer» D. 1.3×10⁻⁸ | |
| 31. |
If pKb for fluoride at 25°c is 10.83, the ionization constant of hydrofluoric acid in water at this temperature is? |
| A. | 3.52×10⁻³ |
| B. | 6.75×10⁻⁴ |
| C. | 5.38×10⁻² |
| D. | 1.74×10⁻⁵ |
| Answer» C. 5.38×10⁻² | |
| 32. |
The hydrolysis constant of CH₃COONa is given by |
| A. | Kh = Kw/Ka |
| B. | Kh = Kw/Kb |
| C. | Kh = Kw/Ka×Kb |
| D. | Kh = Ka + Kb |
| Answer» B. Kh = Kw/Kb | |
| 33. |
The degree of ionization does not depend on? |
| A. | Temperature |
| B. | Current |
| C. | Nature of solvent |
| D. | Concentration |
| Answer» C. Nature of solvent | |
| 34. |
Which of the following acid/base pairs act as natural buffers in living systems? |
| A. | H₂CO₃/HCO₃¯ |
| B. | H₂PO₄-/HPO₄²¯ |
| C. | Histidine+/histidine |
| D. | All of these |
| Answer» E. | |
| 35. |
What is the concentration, in moles/liter, of the hydrogen ion, if pH of a solution is 7? |
| A. | 7 |
| B. | 7 x 10^-7 |
| C. | 5 x 10^-7 |
| D. | 1 x 10^-7 |
| Answer» E. | |
| 36. |
Which of the following alcohols would be most soluble in water? |
| A. | methanol |
| B. | ethanol |
| C. | butanol |
| D. | octanol |
| Answer» B. ethanol | |
| 37. |
Which of the following is a hypertonic solution? |
| A. | Oceans |
| B. | Freshwater habitats |
| C. | 0.45% sodium chloride |
| D. | Red blood cells placed in fresh water |
| Answer» B. Freshwater habitats | |
| 38. |
The processes i and ii are respectively.i) CuSO₄ + 5H₂O → CuSO₄.5H₂Oii) PCl₃ + 3H₂O → H₃PO₃ + 3HCl |
| A. | Hydration and dehydration |
| B. | Hydration and hydrolysis |
| C. | Hydrolysis and hydrolysis |
| D. | Hydration and hydration |
| Answer» C. Hydrolysis and hydrolysis | |
| 39. |
Aqueous solution of the detergents are _________ |
| A. | Neutral |
| B. | Acidic |
| C. | Basic |
| D. | Amphoteric |
| Answer» D. Amphoteric | |
| 40. |
A compound that is capable of forming hydrogen bonds with water |
| A. | is probably held together by noncovalent bonds |
| B. | contains at least some polar covalent bonds |
| C. | should act as a good buffer for acids and bases |
| D. | does not dissolve well in water |
| Answer» C. should act as a good buffer for acids and bases | |
| 41. |
For an acid buffer solution the pH is 3. The pH can be increased by ____________ |
| A. | Increasing the concentration of salt |
| B. | Increasing the concentration of acid |
| C. | Decreasing the concentration of salt |
| D. | Independent of concentration of acid & salt |
| Answer» B. Increasing the concentration of acid | |
| 42. |
What is the heat of vaporization of water? |
| A. | 2260 J/g |
| B. | 2260 kJ/g |
| C. | 1260 J/g |
| D. | 1260 kJ/g |
| Answer» B. 2260 kJ/g | |
| 43. |
If pH of solution of NaOH is 12.0 the pH of H₂SO₄ solution of same molarity will be ____________ |
| A. | 2.0 |
| B. | 12.0 |
| C. | 1.7 |
| D. | 10.0387 |
| Answer» D. 10.0387 | |
| 44. |
Most of the important functional groups in biological molecules contain |
| A. | oxygen and/or nitrogen and are acidic |
| B. | oxygen and a phosphate |
| C. | nitrogen and a phosphate |
| D. | oxygen and/or nitrogen and are polar |
| Answer» E. | |
| 45. |
If protein is made exclusively from nonpolar amino acids, then it will this protein interact with water? |
| A. | be repelled by water |
| B. | It will be attracted to water |
| C. | It will form a membrane in water |
| D. | It will act as a buffer and stabilize the pH |
| Answer» B. It will be attracted to water | |
| 46. |
Identify the triprotic acid from the following. |
| A. | Carbonic acid |
| B. | Bicarbonate |
| C. | Glycine |
| D. | Phosphoric acid |
| Answer» E. | |
| 47. |
What is the factor that is responsible for salts like NaCl to dissolve in water easily? |
| A. | Decrease in entropy |
| B. | Increase in entropy |
| C. | Increase in enthalpy |
| D. | Decrease in enthalpy |
| Answer» C. Increase in enthalpy | |
| 48. |
ΔG is negative for which of the following processes? |
| A. | Melting of ice and evaporation of water |
| B. | Oxidation of nitrogen |
| C. | Oxidation of gold |
| D. | Burning of chlorine |
| Answer» B. Oxidation of nitrogen | |
| 49. |
What makes water a liquid at room temperature? |
| A. | Hydrogen bonds between water molecules |
| B. | Covalent bonding |
| C. | Noncovalent interactions |
| D. | Van der Waals forces of attraction |
| Answer» B. Covalent bonding | |
| 50. |
ΔH is positive for which of the following processes? |
| A. | Oxidation of nitrogen |
| B. | Melting of ice and evaporation of water |
| C. | Oxidation of gold |
| D. | Burning of chlorine |
| Answer» C. Oxidation of gold | |