Here are some Practice MCQ For Government Pharmacist Exams, on acids, bases, and buffers. Use following articles for more details.
Acids, Bases Theory And PH Scale » PHARMACAREERS
Buffer Solution: Buffer Equation And Buffer Capacity » PHARMACAREERS
The buffer capacity of a solution is defined as:
A) The amount of acid or base the buffer can neutralize
B) The pH range over which the buffer is effective
C) The concentration of acid and conjugate base in the buffer
D) The volume of buffer solution used in a reaction
Which of the following is NOT a characteristic of a good buffer?
A) High buffer capacity
B) Minimal change in pH upon dilution
C) Large change in pH upon addition of acid or base
D) Compatibility with biological systems
In pharmaceutical systems, buffers are used to:
A) Maintain the solubility of a drug
B) Stabilize the pH of a solution
C) Enhance the taste of oral medications
D) Both A and B
The Henderson-Hasselbalch equation relates:
A) pH to pKa and the ratio of salt to acid
B) Buffer capacity to pH and pKa
C) Tonicity to osmolarity and pH
D) pKa to the concentration of acid and base
Isotonic solutions are important in pharmaceuticals because:
A) They prevent hemolysis or crenation of red blood cells
B) They enhance drug absorption
C) They increase the shelf-life of drugs
D) They reduce the risk of drug precipitation
To adjust the isotonicity of a solution, one may use:
A) Sodium chloride
B) Dextrose
C) Glycerin
D) All of the above
Buffered isotonic solutions are used for:
A) Oral administration
B) Topical application
C) Parenteral administration
D) Inhalation therapy
The principle behind measuring tonicity is based on:
A) pH measurement
B) Osmolarity measurement
C) Viscosity measurement
D) Conductivity measurement
Which equation would you use to prepare a buffered isotonic solution?
A) Nernst equation
B) Henderson-Hasselbalch equation
C) Van’t Hoff equation
D) Gibbs-Donnan equation
Buffer capacity is highest when:
A) pH = pKa
B) pH > pKa
C) pH < pKa
D) The buffer components are in equal concentrations
The pH of a buffer solution is affected by:
A) Temperature changes
B) The ionic strength of the solution
C) The presence of other solutes
D) All of the above
A buffer solution is most effective when:
A) The ratio of acid to base is 1:1
B) It contains a strong acid and a strong base
C) It is diluted with water
D) The pKa of the acid is far from the desired pH
Which of the following is true about buffer capacity?
A) It is independent of the concentration of buffer components
B) It increases with increasing temperature
C) It decreases with dilution of the buffer solution
D) It is highest when pH = 7
The concept of isotonicity is important in which type of pharmaceutical preparation?
A) Tablets
B) Capsules
C) Injections
D) Ointments
Which method can be used to adjust isotonicity in a pharmaceutical solution?
A) Freezing point depression method
B) Boiling point elevation method
C) Vapor pressure lowering method
D) Osmotic pressure method
When preparing a buffered isotonic solution, it is important to consider:
A) The drug’s stability at different pH levels
B) The buffer’s pKa value in relation to the drug’s pKa value
C) The osmolarity of the final solution
D) All of the above
The osmolarity of a pharmaceutical solution can be measured using:
A) A pH meter
B) An osmometer
C) A viscometer
D) A spectrophotometer
Which type of buffer system is commonly used in blood?
A) Acetic acid/sodium acetate
B) Carbonic acid/bicarbonate
C) Ammonia/ammonium chloride
D) Phosphoric acid/sodium phosphate
Stability testing for buffered solutions often includes:
A) Heat stress testing
B) Freeze-thaw cycle testing
C) pH stability testing
D) All of the above
The process of adjusting isotonicity involves:
A) Increasing the pH to match physiological conditions
B) Adding or removing water from the solution
C) Adjusting the buffer concentration
D) Adding substances with known osmotic coefficients
The buffer index (β) is defined as:
A) d(pH)/d(pKa)
B) d(pH)/d[HA]
C) d(pH)/d(log[A^-])
D) d(pH)/d[Base]
A zwitterionic buffer such as HEPES is often used because:
A) It has a high pKa value
B) It does not interact with biological membranes
C) It can buffer at physiological pH range
D) It is less soluble in water
The Van Slyke equation is used to calculate:
A) Buffer capacity
B) Osmotic pressure
C) Tonicity
D) pKa of a buffer system
In the context of buffer solutions, the term ‘isohydric’ refers to:
A) Solutions with the same pH
B) Solutions with the same buffer capacity
C) Buffers that have the same concentration of hydrogen ions
D) Buffers that have the same concentration of acid and conjugate base
The concept of ‘buffer action’ refers to the ability of a buffer solution to:
A) Change pH rapidly with temperature fluctuations
B) Resist changes in pH upon addition of small amounts of acid or base
C) Increase its volume when an acid or base is added
D) Maintain constant osmolarity despite dilution
Which factor does NOT affect the selection of a buffer system for a pharmaceutical formulation?
A) The pKa value of the buffer components
B) The solubility of the drug substance in the buffer solution
C) The color of the buffer solution
D) The compatibility of the buffer with other formulation components
The physiological pH range is maintained primarily by which buffer system?
A) Acetate buffer
B) Phosphate buffer
C) Bicarbonate buffer
D) Ammonia buffer
When considering buffer systems for parenteral formulations, it is important to ensure:
A) High osmolarity
B) Low osmolarity
C) Non-reactivity with container materials
D) Reactivity with atmospheric gases
The use of Good’s buffers in biological systems is preferred because they:
A) Have high pKa values
B) Are not absorbed by biological membranes
C) Do not interfere with biochemical reactions
D) Can be used at very low concentrations
In a buffered isotonic solution, if the concentration of NaCl is increased, what must be done to maintain isotonicity?
A) Increase the buffer concentration
B) Decrease the buffer concentration
C) Increase the pH of the solution
D) Decrease the volume of the solution
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