(Aldehyde ketones+macromoelcules+reaction kinetics)
1. Which of the following compounds gives a positive Tollens’ test?
A. Propanone
B. Propanal
C. Ethanol
D. Ethanoic acid
2. The functional group present in aldehydes is:
A. –COOH
B. –OH
C. –CHO
D. –CO–
3. Which reagent is commonly used to distinguish an aldehyde from a ketone?
A. NaBH₄
B. Tollens’ reagent
C. H₂SO₄
D. NaCl
4. Acetone on reduction gives:
A. Ethanol
B. Propan-1-ol
C. Propan-2-ol
D. Propanoic acid
5. Oxidation of ethanal produces:
A. Ethanol
B. Ethene
C. Ethanoic acid
D. Methanol
6. Which compound gives a positive iodoform test?
A. Methanal
B. Ethanal
C. Propanal
D. Benzaldehyde
7. Aldehydes and ketones generally undergo:
A. Electrophilic substitution
B. Nucleophilic addition
C. Free-radical substitution
D. Elimination
8. The product formed when an aldehyde reacts with HCN contains:
A. –COOH
B. –CN and –OH
C. –NH₂
D. –NO₂
9. Which of the following is a ketone?
A. CH₃CHO
B. CH₃COCH₃
C. HCHO
D. C₆H₅CHO
10. Formaldehyde is also known as:
A. Methanal
B. Methanone
C. Methanol
D. Methanoic acid
11. The monomer units of proteins are:
A. Glucose
B. Fatty acids
C. Amino acids
D. Nucleotides
12. The bond joining two amino acids is called:
A. Glycosidic bond
B. Peptide bond
C. Ester bond
D. Hydrogen bond
13. Which of the following is a polysaccharide?
A. Glucose
B. Fructose
C. Sucrose
D. Cellulose
14. Glycogen is mainly stored in:
A. Plants
B. Animals
C. Bacteria only
D. Viruses
15. The main structural component of plant cell walls is:
A. Glycogen
B. Starch
C. Cellulose
D. Chitin
16. Sucrose is composed of:
A. Glucose + glucose
B. Glucose + fructose
C. Fructose + fructose
D. Glucose + galactose
17. Which of the following is a reducing sugar?
A. Sucrose
B. Glucose
C. Cellulose
D. Starch
18. The primary structure of a protein refers to:
A. Folding of the polypeptide chain
B. Sequence of amino acids
C. Formation of α-helix only
D. Association of different subunits
19. Which element is characteristically present in proteins but generally absent from carbohydrates?
A. Carbon
B. Hydrogen
C. Nitrogen
D. Oxygen
20. Nucleic acids are polymers of:
A. Amino acids
B. Fatty acids
C. Nucleotides
D. Monosaccharides
21. The rate of a chemical reaction is defined as the change in:
A. Temperature per unit time
B. Concentration per unit time
C. Pressure per unit time
D. Volume per unit time
22. For a zero-order reaction, the rate is:
A. Directly proportional to concentration
B. Inversely proportional to concentration
C. Independent of concentration
D. Proportional to square of concentration
23. The unit of rate constant for a first-order reaction is:
A. mol dm⁻³ s⁻¹
B. s⁻¹
C. dm³ mol⁻¹ s⁻¹
D. mol² dm⁻⁶ s⁻¹
24. The half-life of a first-order reaction is:
A. Directly proportional to initial concentration
B. Independent of initial concentration
C. Inversely proportional to initial concentration
D. Dependent only on pressure
25. A catalyst increases the rate of reaction by:
A. Increasing enthalpy change
B. Increasing the equilibrium constant
C. Lowering activation energy
D. Increasing product concentration
26. The minimum energy required for reactants to undergo a reaction is called:
A. Ionization energy
B. Activation energy
C. Bond energy
D. Lattice energy
27. If the concentration of a reactant is doubled and the reaction rate also doubles, the reaction is likely:
A. Zero order with respect to that reactant
B. First order with respect to that reactant
C. Second order with respect to that reactant
D. Third order with respect to that reactant
28. The overall order of a reaction is determined by:
A. Adding the coefficients of reactants
B. Adding the powers of concentration terms in the rate law
C. Adding molecular masses
D. Number of products formed
29. Which factor does NOT generally affect the rate of a chemical reaction?
A. Temperature
B. Concentration
C. Catalyst
D. Equilibrium constant
30. Increasing temperature generally increases reaction rate because:
A. Activation energy becomes zero
B. More molecules possess energy equal to or greater than activation energy
C. The concentration always increases
D. The equilibrium constant becomes zero
31. For a first-order reaction, the plot of ln[A] against time is:
A. A straight line
B. A parabola
C. A horizontal line
D. A circle
32. If the half-life of a first-order reaction is 10 minutes, the fraction remaining after 30 minutes is:
A. 1/2
B. 1/4
C. 1/8
D. 1/16
33. Molecularity is defined for:
A. Overall reactions only
B. Elementary reactions
C. Reversible reactions only
D. Zero-order reactions only
34. The slowest step in a reaction mechanism is generally called the:
A. Fast step
B. Equilibrium step
C. Rate-determining step
D. Reverse step
35. If the rate law is Rate = k[A]²[B], the overall order of the reaction is:
A. 1
B. 2
C. 3
D. 4
36. Which of the following is a natural polymer?
A. PVC
B. Nylon
C. Cellulose
D. Polythene
37. Starch is a polymer of:
A. Fructose
B. β-glucose
C. α-glucose
D. Amino acids
38. Denaturation of proteins mainly affects their:
A. Amino acid composition
B. Higher-order structures
C. Atomic numbers
D. Peptide bond formation only
39. Which carbohydrate is known as milk sugar?
A. Maltose
B. Lactose
C. Sucrose
D. Fructose
40. Which of the following is NOT a carbohydrate?
A. Glucose
B. Fructose
C. Glycogen
D. Glycerol
41. Which aldehyde is most readily oxidized?
A. Methanal
B. Propanone
C. Benzophenone
D. Acetone
42. 2,4-Dinitrophenylhydrazine is used to identify:
A. Alcohols
B. Aldehydes and ketones
C. Carboxylic acids
D. Amines
43. Which compound does NOT normally give Tollens’ test?
A. Methanal
B. Ethanal
C. Propanal
D. Propanone
44. Reduction of a ketone produces:
A. Primary alcohol
B. Secondary alcohol
C. Tertiary alcohol
D. Carboxylic acid
45. The carbonyl carbon in aldehydes and ketones is:
A. Nucleophilic
B. Electrophilic
C. Neutral
D. Radical
46. A reaction whose rate is independent of the concentration of reactant is:
A. First-order
B. Second-order
C. Zero-order
D. Third-order
47. For a second-order reaction, the unit of rate constant can be:
A. s⁻¹
B. mol dm⁻³ s⁻¹
C. dm³ mol⁻¹ s⁻¹
D. mol dm⁻⁶ s⁻¹
48. A catalyst changes the:
A. Equilibrium position permanently
B. Activation energy
C. Enthalpy of products
D. Chemical formula of reactants
49. Which of the following is an example of a disaccharide?
A. Glucose
B. Fructose
C. Sucrose
D. Glycogen
50. Hydrolysis of a peptide bond produces:
A. Fatty acids
B. Amino acids
C. Monosaccharides
D. Nucleotides