Properties and medicinal uses of inorganic compounds MCQs With Answer

Introduction: For B. Pharm students, mastering the properties and medicinal uses of inorganic compounds is fundamental to pharmaceutical chemistry, pharmaceutics, and clinical pharmacy. Inorganic drugs and excipients—antacids (aluminum hydroxide, magnesium hydroxide), saline cathartics (magnesium sulfate), antiseptics/disinfectants (potassium permanganate, hydrogen peroxide, iodine), astringents/protectives (zinc oxide, alum), radiopaque agents (barium sulfate), fluorides, electrolytes, buffers, and urinary acidifiers/alkalinizers—demand sound knowledge of solubility, hydrates, acid–base behavior, redox reactions, isotonicity (0.9% NaCl), stability, impurities, and toxicity/antidotes (sodium thiosulfate). These concepts guide rational selection, formulation, dosing, compounding, and quality control to meet pharmacopoeial standards and ensure patient safety. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which property makes aluminum hydroxide a preferred non-systemic antacid in long-term therapy?

• Low systemic absorption and sustained neutralizing capacity
• Rapid CO2 release causing gastric distension
• Potent laxative effect through osmotic action
• High alkalinity leading to systemic alkalosis

Correct Answer: Low systemic absorption and sustained neutralizing capacity

Q2. A key disadvantage of sodium bicarbonate as an antacid is:

• Slow onset of action
• Release of CO2 causing belching and potential acid rebound
• Irreversible mucosal damage
• Chelation of dietary iron

Correct Answer: Release of CO2 causing belching and potential acid rebound

Q3. Which pair correctly matches antacid and its common gastrointestinal effect?

• Magnesium hydroxide – diarrhea
• Aluminum hydroxide – diarrhea
• Calcium carbonate – constipation avoided
• Sodium bicarbonate – constipation

Correct Answer: Magnesium hydroxide – diarrhea

Q4. Saline cathartics like magnesium sulfate promote bowel evacuation primarily by:

• Stimulating cholinergic receptors in the gut
• Osmotically retaining water in the intestinal lumen
• Blocking opioid receptors
• Inhibiting sodium-glucose cotransport

Correct Answer: Osmotically retaining water in the intestinal lumen

Q5. Which statement best describes potassium permanganate’s antiseptic action?

• Acts as a surfactant disrupting lipid membranes
• Oxidizes organic substrates, liberating reactive oxygen species
• Chelates essential metals from enzymes
• Precipitates proteins without redox activity

Correct Answer: Oxidizes organic substrates, liberating reactive oxygen species

Q6. The usual household antiseptic strength of hydrogen peroxide is 3% w/v. Its antimicrobial action is due to:

• Formation of hypochlorous acid
• Release of oxygen that oxidizes microbial components
• Chelation of iron from bacterial enzymes
• Protein precipitation with formation of a protective coat

Correct Answer: Release of oxygen that oxidizes microbial components

Q7. Which inorganic compound is a mild antiseptic and eyewash but can be toxic if used extensively on abraded skin or in infants?

• Boric acid
• Sodium bicarbonate
• Zinc oxide
• Magnesium carbonate

Correct Answer: Boric acid

Q8. Zinc oxide’s primary topical pharmaceutical role is as a:

• Counterirritant and rubefacient
• Protective, astringent, and physical UV blocker
• Systemic hematinic
• Potent disinfectant via chlorination

Correct Answer: Protective, astringent, and physical UV blocker

Q9. Which salt is commonly used as an astringent in dilute ophthalmic solutions?

• Zinc sulfate
• Magnesium sulfate
• Sodium sulfate
• Potassium sulfate

Correct Answer: Zinc sulfate

Q10. The caustic and escharotic inorganic compound used for cauterization is:

• Silver nitrate
• Sodium chloride
• Ferrous sulfate
• Magnesium sulfate

Correct Answer: Silver nitrate

Q11. Which agent serves as a sulfur donor antidote in cyanide poisoning?

• Sodium thiosulfate
• Sodium chloride
• Potassium bromide
• Aluminum hydroxide

Correct Answer: Sodium thiosulfate

Q12. Lugol’s iodine contains iodine solubilized with:

• Potassium iodide in water
• Povidone in alcohol
• Sodium thiosulfate in water
• Hydrogen peroxide in alcohol

Correct Answer: Potassium iodide in water

Q13. A recognized adverse effect of potassium iodide therapy is:

• Iodism characterized by metallic taste and salivation
• Severe hypoglycemia
• Irreversible ototoxicity
• Gingival hyperplasia

Correct Answer: Iodism characterized by metallic taste and salivation

Q14. Which inorganic compound is used to prevent dental caries?

• Sodium fluoride
• Sodium chloride
• Sodium nitrite
• Sodium sulfite

Correct Answer: Sodium fluoride

Q15. Barium sulfate is preferred as an oral radiopaque contrast because it is:

• Highly soluble and rapidly absorbed
• Insoluble and not absorbed from the GIT
• A strong osmotic laxative
• Astringent and protein precipitating

Correct Answer: Insoluble and not absorbed from the GIT

Q16. Alum (potash alum) used as a styptic has the formula:

• KAl(SO4)2·12H2O
• Na2CO3·10H2O
• CuSO4·5H2O
• Na2SO4·10H2O

Correct Answer: KAl(SO4)2·12H2O

Q17. Sodium citrate acts as an anticoagulant primarily by:

• Oxidizing hemoglobin
• Complexing ionized calcium
• Inhibiting thrombin directly
• Activating antithrombin III

Correct Answer: Complexing ionized calcium

Q18. The concentration of sodium chloride that is approximately isotonic with blood plasma is:

• 0.45% w/v
• 0.9% w/v
• 1.8% w/v
• 5% w/v

Correct Answer: 0.9% w/v

Q19. Which components in oral rehydration salts provide the main electrolytes?

• Sodium chloride and potassium chloride
• Calcium chloride and magnesium chloride
• Sodium acetate and calcium acetate
• Ammonium chloride and sodium nitrite

Correct Answer: Sodium chloride and potassium chloride

Q20. Ammonium chloride is used therapeutically to:

• Alkalinize urine in cystinuria
• Acidify urine by increasing systemic acid load
• Precipitate cyanide
• Act as an osmotic diuretic

Correct Answer: Acidify urine by increasing systemic acid load

Q21. Sodium bicarbonate enhances urinary excretion of weak acids (e.g., salicylates) by:

• Increasing urinary pH and ionizing the acid
• Decreasing urinary pH and unionizing the acid
• Precipitating the acid as an insoluble salt
• Inhibiting renal transporters directly

Correct Answer: Increasing urinary pH and ionizing the acid

Q22. A disadvantage of calcium carbonate as an antacid is:

• Severe hypocalcemia
• Acid rebound and risk of hypercalcemia
• Profuse diarrhea
• Irreversible renal failure at therapeutic doses

Correct Answer: Acid rebound and risk of hypercalcemia

Q23. Which compound is strongly deliquescent and used as a drying agent (desiccant)?

• Calcium chloride
• Sodium chloride
• Zinc oxide
• Barium sulfate

Correct Answer: Calcium chloride

Q24. Kaolin (light kaolin) exerts antidiarrheal action mainly by:

• Direct antibacterial killing
• Adsorption of toxins and water
• Opioid receptor agonism
• Blocking chloride channels

Correct Answer: Adsorption of toxins and water

Q25. Potassium nitrate in desensitizing toothpaste reduces sensitivity by:

• Remineralizing enamel directly
• Blocking dentinal tubules physically
• Depolarizing nerve endings via increased extracellular K+
• Forming a protective protein layer

Correct Answer: Depolarizing nerve endings via increased extracellular K+

Q26. 0.9% sodium chloride (“normal saline”) is commonly used for:

• Replacing free water deficits
• Vehicle and irrigation compatible with tissues
• Parenteral nutrition
• Chelation therapy

Correct Answer: Vehicle and irrigation compatible with tissues

Q27. Hydrogen peroxide solution should be stored in:

• Clear glass exposed to light
• Light-resistant containers to minimize decomposition
• Metallic containers to catalyze release of oxygen
• Open containers to vent pressure

Correct Answer: Light-resistant containers to minimize decomposition

Q28. The principal germicidal species produced when chlorine is dissolved in water is:

• Chloride ion (Cl−)
• Hypochlorous acid (HOCl)
• Chlorate (ClO3−)
• Dichloride radical (Cl2•−)

Correct Answer: Hypochlorous acid (HOCl)

Q29. Bleaching powder used for disinfection is chemically best described as:

• Calcium oxychloride containing available chlorine
• Sodium hypochlorite dihydrate
• Calcium carbonate
• Calcium chlorate

Correct Answer: Calcium oxychloride containing available chlorine

Q30. Sodium thiosulfate is used in pharmaceutical analysis to:

• Titrate iodine in iodometry as a reducing agent
• Precipitate chloride as AgCl
• Oxidize Fe2+ to Fe3+
• Buffer solutions at pH 7.4

Correct Answer: Titrate iodine in iodometry as a reducing agent

Q31. Which inorganic astringent is used in Burow’s solution for topical inflammatory conditions?

• Aluminum subacetate
• Magnesium hydroxide
• Sodium acetate
• Potassium acetate

Correct Answer: Aluminum subacetate

Q32. Ferrous sulfate is preferred over ferric salts as an oral hematinic because ferrous iron:

• Is less soluble at gastric pH
• Is better absorbed in the duodenum
• Does not interact with food
• Has no gastrointestinal side effects

Correct Answer: Is better absorbed in the duodenum

Q33. On reduction, the purple solution of potassium permanganate typically:

• Remains purple without change
• Becomes brown due to MnO2 formation
• Turns bright red due to Mn2O7
• Becomes blue due to Cu2+

Correct Answer: Becomes brown due to MnO2 formation

Q34. Which inorganic antiseptic has been largely abandoned for routine use due to significant toxicity?

• Mercuric chloride
• Hydrogen peroxide
• Boric acid
• Potassium permanganate

Correct Answer: Mercuric chloride

Q35. In barium salt poisoning (e.g., barium chloride ingestion), an immediate measure is to administer:

• Sodium sulfate to precipitate insoluble barium sulfate
• Sodium chloride to increase solubility
• Sodium bicarbonate to alkalinize
• Potassium iodide to form barium iodide

Correct Answer: Sodium sulfate to precipitate insoluble barium sulfate

Q36. For iodization of table salt, the compound preferred for stability in humid, hot climates is:

• Potassium iodate
• Potassium iodide
• Sodium iodide
• Iodine tincture

Correct Answer: Potassium iodate

Q37. Selenium sulfide is used topically to manage:

• Onychomycosis
• Seborrheic dermatitis and pityriasis versicolor
• Genital warts
• Acne vulgaris

Correct Answer: Seborrheic dermatitis and pityriasis versicolor

Q38. Which pair correctly matches salt and traditional name?

• Magnesium sulfate – Epsom salt
• Sodium sulfate – Blue vitriol
• Copper sulfate – Glauber’s salt
• Zinc sulfate – Washing soda

Correct Answer: Magnesium sulfate – Epsom salt

Q39. Which inorganic compound acts as a protective and astringent in diaper rash preparations?

• Zinc oxide
• Ferrous sulfate
• Potassium nitrate
• Sodium chloride

Correct Answer: Zinc oxide

Q40. Identify the systemic antacid from the list:

• Sodium bicarbonate
• Aluminum hydroxide
• Magnesium hydroxide
• Zinc carbonate

Correct Answer: Sodium bicarbonate

Q41. In compounding ophthalmic solutions, a common buffer pair used for pH adjustment is:

• Sodium dihydrogen phosphate and disodium hydrogen phosphate
• Sodium acetate and calcium acetate
• Ammonium chloride and sodium chloride
• Magnesium sulfate and sodium sulfate

Correct Answer: Sodium dihydrogen phosphate and disodium hydrogen phosphate

Q42. Nitrous oxide (N2O) is used primarily as a/an:

• Topical antiseptic
• Inhalational analgesic/anesthetic adjunct
• Radiopaque diagnostic agent
• Oxygen therapy enhancer via chemical reaction

Correct Answer: Inhalational analgesic/anesthetic adjunct

Q43. Sodium nitroprusside is used in hypertensive emergencies. A key safety consideration is:

• Risk of cyanide toxicity; co-administration of sodium thiosulfate may be needed
• Severe bronchospasm due to cholinergic effects
• Irreversible platelet inhibition
• Accumulation of elemental iodine

Correct Answer: Risk of cyanide toxicity; co-administration of sodium thiosulfate may be needed

Q44. Which compound is used to neutralize iodine stains and as an antidote in iodine exposure?

• Sodium thiosulfate
• Sodium chloride
• Potassium permanganate
• Calcium carbonate

Correct Answer: Sodium thiosulfate

Q45. The mechanism by which alum acts as a styptic is via:

• Oxidation of hemoglobin
• Protein precipitation causing vasoconstriction and hemostasis
• Chelation of iron in blood
• Formation of oxygen free radicals

Correct Answer: Protein precipitation causing vasoconstriction and hemostasis

Q46. Which statement about barium sulfate as a contrast medium is TRUE?

• It is contraindicated when GI perforation is suspected
• It is safely absorbed and excreted renally
• It dissolves in gastric acid to enhance contrast
• It chelates calcium causing hypocalcemia

Correct Answer: It is contraindicated when GI perforation is suspected

Q47. The optimal fluoride concentration in community water to prevent dental caries without fluorosis is approximately:

• 0.1 ppm
• 0.7–1.0 ppm
• 2.5–3.0 ppm
• 5.0 ppm

Correct Answer: 0.7–1.0 ppm

Q48. Which inorganic bismuth salt has been used as a mild astringent and protective in GI formulations?

• Bismuth subnitrate
• Bismuth subsalicylate
• Bismuth citrate
• Bismuth chloride

Correct Answer: Bismuth subnitrate

Q49. A pharmacist combines aluminum hydroxide with magnesium hydroxide in an antacid to:

• Increase systemic alkalosis
• Balance constipation and diarrhea effects
• Enhance CO2 release
• Increase gastric acid secretion

Correct Answer: Balance constipation and diarrhea effects

Q50. Match each common name with the correct salt:

• Blue vitriol – Copper sulfate
• Glauber’s salt – Sodium sulfate
• Washing soda – Sodium carbonate
• All of the above

Correct Answer: All of the above