Electrolytes in replacement therapy: Sodium chloride* MCQs With Answer

Electrolytes in replacement therapy: Sodium chloride* MCQs With Answer is a focused resource for B. Pharm students to master fluid and electrolyte balance, IV therapy, and clinical pharmacology. This guide covers sodium chloride solutions (0.9%, 0.45%, 3%), isotonic vs hypotonic vs hypertonic fluids, osmolarity, distribution across body compartments, acid–base effects, indications (hypovolemia, hyponatremia), contraindications (hypernatremia, edema), infusion safety, and monitoring. Key keywords include sodium chloride, normal saline, hypertonic saline, electrolyte replacement therapy, osmolarity, extracellular fluid, hyponatremia correction, hyperchloremic metabolic acidosis, and ORS. Build exam confidence and clinical reasoning with precise facts, calculations, and scenario-based questions. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which IV fluid is considered isotonic and commonly used for initial volume resuscitation?

• 0.9% sodium chloride (normal saline)
• 3% sodium chloride
• 0.45% sodium chloride
• Sterile water for injection

Correct Answer: 0.9% sodium chloride (normal saline)

Q2. What are the approximate sodium and chloride concentrations in 0.9% sodium chloride?

• 77 mEq/L sodium and 77 mEq/L chloride
• 100 mEq/L sodium and 100 mEq/L chloride
• 154 mEq/L sodium and 154 mEq/L chloride
• 200 mEq/L sodium and 200 mEq/L chloride

Correct Answer: 154 mEq/L sodium and 154 mEq/L chloride

Q3. The osmolarity of 0.9% sodium chloride is closest to:

• 154 mOsm/L
• 250 mOsm/L
• 308 mOsm/L
• 600 mOsm/L

Correct Answer: 308 mOsm/L

Q4. Isotonic saline primarily expands which body fluid compartment?

• Intracellular fluid compartment
• Extracellular fluid compartment
• Both intracellular and extracellular equally
• Only intravascular plasma volume without interstitial expansion

Correct Answer: Extracellular fluid compartment

Q5. A primary indication for 3% sodium chloride is:

• Asymptomatic mild hyponatremia
• Severe symptomatic hyponatremia with seizures
• Routine maintenance fluid therapy
• Treating hypernatremia

Correct Answer: Severe symptomatic hyponatremia with seizures

Q6. Which is a potential adverse effect of large-volume 0.9% sodium chloride infusion?

• Metabolic alkalosis
• Hyperchloremic metabolic acidosis
• Hypochloremia
• Severe hyperkalemia

Correct Answer: Hyperchloremic metabolic acidosis

Q7. In chronic hyponatremia, the recommended maximum increase in serum sodium over the first 24 hours is:

• ≤4 mEq/L
• ≤6 mEq/L
• ≤8 mEq/L
• ≤15 mEq/L

Correct Answer: ≤8 mEq/L

Q8. The sodium content of 3% sodium chloride is approximately:

• 154 mEq/L
• 300 mEq/L
• 513 mEq/L
• 900 mEq/L

Correct Answer: 513 mEq/L

Q9. Which statement best describes 0.45% sodium chloride?

• Isotonic crystalloid
• Hypotonic crystalloid
• Hypertonic crystalloid
• Colloid solution

Correct Answer: Hypotonic crystalloid

Q10. For hypovolemic hyponatremia, the preferred initial therapy is:

• 0.45% sodium chloride
• 0.9% sodium chloride
• D5W
• Sterile water bolus

Correct Answer: 0.9% sodium chloride

Q11. Which condition is a relative contraindication to aggressive sodium chloride-based fluid loading?

• Hypovolemic shock
• Hypernatremia
• Septic shock
• Acute blood loss

Correct Answer: Hypernatremia

Q12. WHO low-osmolarity ORS contains approximately what sodium concentration?

• 45 mEq/L
• 60 mEq/L
• 75 mEq/L
• 110 mEq/L

Correct Answer: 75 mEq/L

Q13. For severe symptomatic hyponatremia in adults, an initial bolus of 3% NaCl often recommended is:

• 50 mL over 30 minutes
• 100 mL over 10 minutes (may repeat up to 3 times)
• 250 mL over 1 hour
• 500 mL over 2 hours

Correct Answer: 100 mL over 10 minutes (may repeat up to 3 times)

Q14. Large volumes of normal saline can decrease the strong ion difference and cause:

• Respiratory alkalosis
• Metabolic alkalosis
• Hyperchloremic metabolic acidosis
• Respiratory acidosis

Correct Answer: Hyperchloremic metabolic acidosis

Q15. Which IV solution is compatible for use with blood transfusions?

• 0.9% sodium chloride
• Lactated Ringer’s
• D5W
• 0.45% sodium chloride with potassium

Correct Answer: 0.9% sodium chloride

Q16. One liter of 0.9% sodium chloride contains how many grams of NaCl?

• 4.5 g
• 6.0 g
• 9.0 g
• 12.0 g

Correct Answer: 9.0 g

Q17. The sodium content delivered by 1 liter of normal saline is:

• 77 mEq
• 100 mEq
• 154 mEq
• 300 mEq

Correct Answer: 154 mEq

Q18. Which fluid is preferred for initial resuscitation in hypovolemic shock?

• 0.9% sodium chloride
• 0.45% sodium chloride
• D5W
• Sterile water

Correct Answer: 0.9% sodium chloride

Q19. In adults, typical daily maintenance sodium requirement is approximately:

• 0.5 mEq/kg/day
• 1–2 mEq/kg/day
• 3–4 mEq/kg/day
• 5–6 mEq/kg/day

Correct Answer: 1–2 mEq/kg/day

Q20. 3% sodium chloride should preferably be administered via:

• Peripheral vein without monitoring
• Central venous access with monitoring
• Subcutaneous infusion
• Intramuscular injection

Correct Answer: Central venous access with monitoring

Q21. After metabolism of dextrose, D5W behaves physiologically as:

• Free water distributing across all body compartments
• Purely intravascular expander
• Strictly extracellular fluid expander
• Colloid solution

Correct Answer: Free water distributing across all body compartments

Q22. Which solution is safer for routine pediatric maintenance to minimize hospital-acquired hyponatremia?

• 0.45% sodium chloride
• 0.9% sodium chloride
• D5W alone
• Sterile water with electrolytes

Correct Answer: 0.9% sodium chloride

Q23. Sodium is the principal cation of which compartment?

• Intracellular fluid
• Extracellular fluid
• Transcellular fluid only
• All compartments equally

Correct Answer: Extracellular fluid

Q24. Chloride is best described as the major:

• Intracellular anion
• Extracellular anion
• Intracellular cation
• Buffer in red blood cells only

Correct Answer: Extracellular anion

Q25. Which condition is best managed initially with isotonic saline to correct chloride-responsive alkalosis?

• Metabolic alkalosis due to vomiting
• Metabolic acidosis due to diarrhea
• Respiratory alkalosis
• Respiratory acidosis

Correct Answer: Metabolic alkalosis due to vomiting

Q26. The total body water fraction used in sodium deficit calculation for an average adult male is approximately:

• 0.4 × body weight (kg)
• 0.5 × body weight (kg)
• 0.6 × body weight (kg)
• 0.7 × body weight (kg)

Correct Answer: 0.6 × body weight (kg)

Q27. The commonly used formula to estimate the change in serum sodium with infusate is the:

• Henderson–Hasselbalch equation
• Adrogue–Madias formula
• Fick’s law
• Nernst equation

Correct Answer: Adrogue–Madias formula

Q28. Among isotonic crystalloids, which has the highest chloride concentration?

• 0.9% sodium chloride
• Lactated Ringer’s
• Plasma-Lyte
• D5W

Correct Answer: 0.9% sodium chloride

Q29. Which statement about 0.9% sodium chloride is true?

• It is isotonic and chloride-rich compared to plasma
• It is hypotonic and potassium-rich
• It is hypertonic relative to plasma at all times
• It distributes primarily into the intracellular space

Correct Answer: It is isotonic and chloride-rich compared to plasma

Q30. How many grams of NaCl are in 1 liter of 0.45% sodium chloride?

• 2.25 g
• 4.5 g
• 6.75 g
• 9.0 g

Correct Answer: 4.5 g

Q31. In acute traumatic brain injury, which crystalloid is generally preferred to avoid lowering serum sodium?

• 0.9% sodium chloride
• 0.45% sodium chloride
• D5W
• Sterile water

Correct Answer: 0.9% sodium chloride

Q32. Which best describes the distribution of 1 liter of 0.9% sodium chloride after infusion?

• Mostly intracellular
• Expands extracellular fluid; about one-quarter intravascular, three-quarters interstitial
• Equally intracellular and extracellular
• Only intravascular

Correct Answer: Expands extracellular fluid; about one-quarter intravascular, three-quarters interstitial

Q33. Rapid correction of hypernatremia primarily risks:

• Osmotic demyelination syndrome
• Cerebral edema
• Hyperchloremic acidosis
• Hyperkalemia

Correct Answer: Cerebral edema

Q34. The safe target for correction of chronic hypernatremia is generally:

• ≤4 mEq/L per day
• ≤8–10 mEq/L per day
• ≤15 mEq/L per day
• Any rate if neurologically intact

Correct Answer: ≤8–10 mEq/L per day

Q35. In severe dehydration due to diarrhea, initial IV fluid recommended is:

• Isotonic crystalloid such as 0.9% sodium chloride
• D5W
• 0.45% sodium chloride
• Sterile water bolus

Correct Answer: Isotonic crystalloid such as 0.9% sodium chloride

Q36. Compared with normal saline, Lactated Ringer’s:

• Has higher chloride concentration
• Is a more “balanced” solution with buffer anions
• Is hypertonic relative to plasma
• Contains no electrolytes

Correct Answer: Is a more “balanced” solution with buffer anions

Q37. For severe symptomatic SIADH, initial management may include:

• Fluid restriction alone
• 3% sodium chloride with careful monitoring
• 0.45% sodium chloride bolus
• D5W infusion

Correct Answer: 3% sodium chloride with careful monitoring

Q38. In hypercalcemia, an effective initial therapy includes:

• 0.9% sodium chloride hydration followed by loop diuretics
• D5W only
• 0.45% sodium chloride infusion
• Immediate thiazide diuretics

Correct Answer: 0.9% sodium chloride hydration followed by loop diuretics

Q39. For cholera with severe dehydration, the preferred crystalloid is:

• Lactated Ringer’s
• 0.45% sodium chloride
• D5W
• Sterile water

Correct Answer: Lactated Ringer’s

Q40. Which statement about 3% sodium chloride is correct?

• It is hypotonic compared to plasma
• It risks phlebitis if infused peripherally at high rates
• It has 154 mEq/L sodium
• It should be used freely without monitoring

Correct Answer: It risks phlebitis if infused peripherally at high rates

Q41. Hospital-acquired hyponatremia is most associated with which maintenance fluid strategy?

• Isotonic maintenance fluids
• Hypotonic maintenance fluids such as 0.45% NaCl
• No fluids
• Colloid maintenance fluids

Correct Answer: Hypotonic maintenance fluids such as 0.45% NaCl

Q42. Which parameter is essential to monitor during sodium chloride replacement therapy?

• Serum sodium concentration
• Serum bilirubin
• Serum amylase
• Serum uric acid

Correct Answer: Serum sodium concentration

Q43. The main risk of overly rapid correction of chronic hyponatremia is:

• Central pontine (osmotic) demyelination
• Acute renal failure
• Rhabdomyolysis
• Hyperkalemia

Correct Answer: Central pontine (osmotic) demyelination

Q44. In which scenario is 0.45% sodium chloride most appropriate?

• Acute hypovolemic shock
• Treatment of hypernatremia with volume repletion
• Acute traumatic brain injury resuscitation
• Severe hyponatremic seizures

Correct Answer: Treatment of hypernatremia with volume repletion

Q45. Which isotonic crystalloid has composition closer to plasma with lower chloride than NS?

• 0.9% sodium chloride
• Lactated Ringer’s
• D5W
• 3% sodium chloride

Correct Answer: Lactated Ringer’s

Q46. A pharmacist should avoid mixing which of the following directly with hypotonic saline due to hemolysis risk?

• Red blood cells
• Potassium chloride
• Magnesium sulfate
• Vitamin B complex

Correct Answer: Red blood cells

Q47. Compared to plasma, 0.9% sodium chloride is best described as:

• Balanced in chloride and buffer content
• Chloride-rich and buffer-poor
• Potassium-rich
• Hypotonic

Correct Answer: Chloride-rich and buffer-poor

Q48. Which solution is a crystalloid?

• 0.9% sodium chloride
• Albumin 5%
• Dextran 70
• Hydroxyethyl starch

Correct Answer: 0.9% sodium chloride

Q49. For pediatric severe symptomatic hyponatremia, a commonly recommended initial bolus is:

• 3% sodium chloride 1 mL/kg
• 3% sodium chloride 2 mL/kg
• 3% sodium chloride 5 mL/kg
• 0.9% sodium chloride 10 mL/kg

Correct Answer: 3% sodium chloride 2 mL/kg

Q50. Which of the following best explains why NS can worsen metabolic acidosis?

• Excess bicarbonate content
• High chloride lowers strong ion difference and bicarbonate
• High potassium increases acid load
• It increases lactate production

Correct Answer: High chloride lowers strong ion difference and bicarbonate