Chapter 5: Drug Stability – Chemical Kinetics
1. A graph is plotted by taking time on x axis and concentration of reactant on y axis for a reaction following a pseudo first order. The pattern of the
graph is:
A. curve
B. hyperbola
C. parabola
D. straight line
Ans:A
2. In the photochemical degradation of multisulpha preparation, the order that the reaction follows is:
A. first
B. pseudo first
C. second
D. zero
Ans:D
3. The integral rate equation for a reaction (in common notation) is written as log C = log Co – (kt/2.303). When a graph is drawn log c vs. t, the slope will be:
A. negative
B. one
C. Positive
D. Zero
Ans:A
4. The integral equation (in common notation) k = x/at (a – x) is concerned with the order:
A. first
B. pseudo first
C. second
D. zero
Ans:C
5. When a series of steps are involved in a reaction, the ‘overall rate’ of a reaction depends upon the rate(s) of:
A. all steps
B. all steps which follow the slowest step
C. all steps which precede the slowest step
D. the slowest step
Ans:C
6. The solid state decomposition of aspirin in presence of moisture follows the order:
A. first
B. pseudofirst
C. second
D. zero
Ans:D
7. The reaction rate constant (k) is 2.0 x 10-3 min.-1 for aspirin hydrolysis in 0.1 N hydrochloric acid at 1mg/ml concentration. Under same conditions, if the product contains aspirin 4 mg/ml of the initial concentration, the k value in minutes-1 will be:
A. 0.5 x l0-3
B. 2.0 x 10-3
C. 4.0 x 10-3
D. 8.0 x 10-3
Ans:B
8. A second order reaction follows pseudo-first order reaction, when the concentrations of:
A. two reactants are high
B. two reactants are low
C. one reactant is far higher than the other reactant.
D. two reactants are equal
Ans:C
9. In the study of the rate of a reaction, 100 ml of 0.1 N hydrochloric acid is added to 10 ml methyl acetate for the reaction to occur. The reason for making such a proportion is to make:
A. analysis of degradation is easy
B. reaction to follow first order
C. reaction to proceed slowly
D. reaction to undergo a pseudo first order
Ans:D
10. The conversion of trans-stilbene to cis-stilbene follows the molecularity:
A. bimolecular
B. termolecular
C. unimolecular
D. zeromolccular
Ans:C
11. In the hydrolysis of sucrose in hydrochloric acid solution, the change in the optical rotation follows the order:
A. pseudofirst
B. pseudo zero
C. second
D. zero
Ans:A
12. In the degradation studies of aspirin suspension, the orders observed initially and at the end, respectively, are: –
A. first, second
B. first, zero
C. second, first
D. zero, first
Ans:D
13. A prescription of liquid aspirin preparation contained 6.5 g/100 ml. The solubility of aspirin at 25°C is 0.33 g/100 ml. The order of reaction in the kinetic study is:
A. apparent first B. apparent zero
C. first D. second
Ans:B
14. The time required for the complete degradation of a drug in solution is a finite value. The order of that reaction is:
A. first
B. pseudo first
C. second
D. zero
Ans:D
15. Normally, ethyl acetate undergoes hydrolysis in presence of H+ and (OH)- ions. The order of the reaction observed in the acidic and alkaline solutions, respectively, are:
A. first and second
B. pseudo first and second
C. second and first
D. second and pseudo first
Ans:B
16. In reactions that follow first order kinetics, half life is expressed by equation:
A. 0.693/k1
B. 0.301/k1
C. 0.105/k1
D. k1/0.693
Ans:A
17. The units for the specific rate constant for a second order reaction are:
A. liter/moles.sec
B. liter.sec/moles
C. moles/liter.sec
D. moles.sec/liter
Ans:A
18 The half life of a first order reaction is 4 years. What is its shelf life (in years)?
A. 0.02
B. 0.03
C. 0.17
D. 0.61
Ans:D
19. The general rate expression for a first order reaction (in common notation) is.
A. dc/dt = -kC
B. ???? = 2.303 / ???? log ????0 / ????????
C. ???? = 1 / ???????? ???? / (????−????)
D. dc/dt = k
Ans:A
20. Which one of the following dosage forms exhibit faster rate of reaction under normal conditions?
A. emulsions
B. ointments
C. solutions
D. suspensions
Ans:C
21. In chemical kinetics, the rate of a reaction is expressed as (-dc/dt), where dc refers to the concentration. Whose concentration does it refer to?
A. catalyst
B. product
C. reactant
D. solvent medium
Ans:C
22. Which one of the following can be designated as the molecularity of a reaction?
A. half
B. one
C. one and half
D. zero
Ans:B
23. Which one of them is refered as a general rate equation (-dc/dt) for a second order?
A. A°B°
B. A1B1
C. A 1B2
D. A 2B 2
Ans:B
24. Which-one of the following orders have abundant applications in biological processes?
A. first
B. second
C. third
D. zero
Ans:A
25. In a chemical reaction, the rate constant is independent of the initial concentration. Which one of them is the order?
A. first
B. second
C. third
D. zero
Ans:D
26. Chemical kinetics is the study of the
a. rate of chemical reactions
b. particle size
c. rheological property
d. interfacial tension
Ans:a
27. Rate of reaction is the
a. number of reactant molecules or atoms that take part in chemical reactions to give the products.
b. sum of exponents or powers of concentration terms in the rate equation
c. time required for reactant concentration to decrease to 90% of the initial concentration.
d. speed at which chemical reaction takes place
Ans:d
28. When rate is independent of the reactant concentration, then it is called
a. zero order reaction.
b. Pseudo zero order reaction
c. First order reaction
d. Second order reaction
Ans:a
29. In the equation, Rate = k[C]c
[D]d, the order of the above reaction is
a. k
b. C + D
c. [C] *[D]
d. c + d
Ans:d
30. Which of the following is the half life of zero order reaction
a. t1/2 = Ao/2k
b. t1/2 = 0.693/2k
c. t1/2 = Ao/2
d. t1/2 = 2k/ Ao
Ans:a
31. The unit of k for zero order reaction is
a. moles/litre/second
b. moles
c. moles/second
d. moles/litre
Ans:a
32. Which of the following is the half life of first order reaction
a. t1/2 = A0/2k
b. t1/2 = 0.693/2k
c. t1/2 = 2k
d. t1/2 = 0.693/k
Ans:d
33. The unit of rate constant for second order reaction is
a. litre.mole-2 sec-2
b. litre.mole-2 sec-1
c. litre
d. litre.mole-1 sec-1
Ans:d
34. Which of the following method/s used for determination of order of reaction?
a. Graphic method
b. Substitution method
c. Half life method
d. All of the above –
Ans:d
35. The value of t1/2 for second order reaction is
a. 1/ak. b. 0.693/k
c. Ao/2k d. Ao/2
Ans:a
Chapter 5: Drug Stability MCQs with Answer
1. The accelerated stability studies are primarily used to determine:
A. energy of the activation of the reaction
B. k value at elevated temperatures
C. k value at the room temperature
D. shelf life of the product
Ans:D
2. The specific rate constant (k) determined for aspirin hydrolysis in pH 1.0 buffer at 1 mg/ml concentration is 2.0×10-3 min-1 at 25°C. The shelf life of the product is (in minutes):
A. 2.0
B. 52
C. 104
D. 346
Ans:B
3. Identify the equation that is NOT of Arrhenius:
A. ln ???? = −???????? / 2.303???????? + ln ????
B. ln ???? = −???????? / ???????? + ln ????
C. log ???? = −???????? / 2.303???????? + log ????
D. k = A???? −????????/????????
Ans:A
4. In general, reaction rate constants in neutral pH are comparatively:
A. equal
B. higher
C. lower
D. zero
Ans:C
5. The expiry date for a tablet is not mentioned on the label. It means that the expiry time in years is:
A. five years
B. nil
C. three years
D. two years
Ans:A
6. Penicillin G is prepared as a salt of procaine penicillin G. Now the rate of decomposition of penicillin
G will be:
A. increased
B. reduced
C. unchanged
D. unpredictable
Ans:B
7. According to International Pharmaceutical Federation, the recommended overages be limited to the maximum percent of:
A. five
B. ten
C. thirty
D. twenty
Ans:C
8. Usually, the rate of a chemical reaction may be enhanced by:
A. cooling the reaction mixture
B. increasing the rate of stirring
C. raising the temperature of the reaction mixture
D. using stoichiometric quantities of each reactant
Ans:C
9. Which of the following expression is correct for the determination of shelf life for a first order decomposition?
A. t1/2 = 0.105/k
B. t90 = 0.693/k
C. t1/2 = 0.693/k
D. t90 = 0.105/k
Ans:D
10. Regarding the influence of the solvent on the rate of reaction, solvents having the internal pressure:
A. HIGHER produce products with HIGHER internal pressure
B. HIGHER favour the formation of products having LOWER internal pressure
C. LOWER yield products having HIGHER internal pressure
D. LOWER retard the formation of products with LOWER internal pressure
Ans:A
11. During autoclaving of dextrose solution, a straw colour is observed. It is due to the presence of a substance called:
A. furfural
B. 5-hydroxymethylfurfural
C. 5-hydroxyfurfural
D. 5-methylfurfural
Ans:B
12. In injections, procaine undergoes the degradation reactions in the following sequence:
A. decarboxylation and hydrolysis
B. hydrolysis and decarboxylation
C. hydrolysis, decarboxylation and oxidation
D. oxidation, decarboxylation and hydrolysis
Ans:B
13. On a product, the label states ‘protect from light’. What type of decomposition does the product undergo?
A. carboxylation
B. decarboxylation
C. hydrolysis
D. oxidation
Ans:D
14. Which of the following reactions is observed in the degradation of ampicillin?
A. decarboxylation
B. hydrolysis
C. oxidation
D. recimization
Ans:B
15. Aspirin undergoes decomposition in a formulation. It can be prevented by:
A. adding a chelating agent
B. adding an antioxidant
C. protecting it from light
D. suppressing its solubility
Ans:D
16. Which one of the following is primarily NOT a chemical decomposition?
A. isomerisation
B. hydrolysis
C. oxidation
D. volatilization
Ans:D
17. For the validity of accelerated stability studies of solution dosage form, the energy of activation should be in the range of (in units of kcal/mole).
A. 0 to 10
B. 11 to 30
C. 31 to 50
D. 51 to 70
Ans:B
18. Which one of these methods is the MOST effective in preventing the rate of hydrolysis?
A. buffer
B. complexation
C. removal of water
D. suppression of solubility
Ans:C
19. During storage, crystal growth is observed in a suspension due to:
A. absorption of water
B. fluctuations in the ambient temperatures
C. presence of suspending agent
D. volatilization of solids
Ans:B
20. The storage directions on a parenteral solution specify ‘store in a cool place’. This may be stored in:
A. an air-conditioned area at 10°C
B. a refrigerator at 15°C
C. a place whose temperature is set at 5°C
D. room temperature, at 25°C
Ans:B
21. which of the following is cause of physical degradation of drug?
a. volatilisation of components during storage
b. Changes from one state to another
c. Change in colour
d. All of the above
Ans:d
22. Which of the following factors affect the rate of reaction?
a. Temperature
b. Catalysis
c. Dielectric constant
d. All of the above
Ans:d
23. The effect of temperature on rate of reaction is explained by
a. Arrhenius equation
b. Nernst equation
c. Noyes Whitney equation
d. Fick’s first law
Ans:a
24. The unit of activation energy is
a. kJ/mol
b. J
c. N/m
d. mm
Ans:a
25. The dielectric constant is used to measure
a. Viscosity of solvent
b. polarity of the solvent
c. temperature of solvent
d. flowability of solvent
Ans:b
26. Accelerated stability testing is done to
a. predict shelf of the formulation
b. Predict dissociation constant
c. Predict diffusion constant
d. Determine activation energy
Ans:a
27. ICH stands for
a. Indian council on harmonisation
b. International Conference On Harmonisation
c. Inter Cranial Healer
d. None of the above
Ans:b
28. Stability Data for Climatic zone III & IV comes under___________ICH guideline
a. Q1C
b. Q1E
c. Q1F
d. Q1D
Ans:c
29. Climatic zone II is
a. Moderate climate
b. Subtropical and Mediterranean climate
c. Hot/dry climate
d. Hot/humid climate
Ans:b
30. Stability testing is done
a. to determine shelf life of product
b. to determine the components used for packaging
c. to get information at preformulation stage
d. All of the above
Ans:d
31………… is the time necessary for the concentration of the reactant to decrease to 90% of its original concentration.
(a) Product life
(b) Shelf life
(c) Half life
(d) None of the above
Ans:b
32. Generally, Stability testing is employed for………..
(a) Delivering evidences of the change in quality of the drug product with time.
(b) Confirming shelf life for the drug product.
(c) Determining container closure system suitability.
(d) All of the above
Ans:d
33. A zero-order reaction is a reaction having rate of concentration of reactant.
(a) Dependent
(b) Partially dependent
(c) Independent
(d) None of the above
Ans:c
34. In a second-order reaction, the sum of the exponents in the rate law is equal to……………
(a) Zero
(b) One
(c) Two
(d) Three
Ans:c
35………..technique is utilized only during determination of order of reaction, when the rate law involved
by only single concentration term.
(a) The concentration
(b) The half of the concentration
(c) The square of the concentration
(d) None of the above
Ans:c
36 ………..technique is utilized only when the rate law involved by only single concentration term for determination of order of reaction.
(a) Half Life Method
(b) Graphical Method
(c) Initial Rate Method
(d) Van’t Hoff Differential Method
Ans:a
37 ……… technique is utilized in presence single reactant for determination of order of reaction.
(a) Half Life Method
(b) Graphical Method
(c) Initial Rate Method
(d) Van’t Hoff Differential Method
Ans:b
38. In exothermic Reaction, if we increase the temperature in the exothermic reaction the rate of reaction
will………
(a) Increases
(b) Decrease
(c) Remains constant
(d) None of the above
Ans:b
39. If ions of similar charges involve in reaction it will…………rate of reaction.
(a) Increases
(b) Decreases
(c) Remains constant
(d) None of the above
Ans:b
40. The drug molecule is degradate by exposure of light it affects substantial degradation of drug molecule this phenomenon is known as………..
(a) Photolytic degradation
(b) Chemical degradation
(c) Physical degradation
(d) None of the above
Ans:a
Subject:- Physical pharmaceutics 2 MCQs with Answer
Topic:- Drug Stability MCQs with Answer (Unit:- 5 MCQs)
