Toxicology: potassium permanganate: practice question

A Forensic Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Forensic Medicine · Toxicology: potassium permanganate

Sample item

A man swallows purple crystals dissolved in water. He has brown-black staining of the lips and tongue, hoarseness from laryngeal oedema and burning epigastric pain. Which poison is most likely?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Potassium permanganate

Potassium permanganate is a strong oxidiser that stains the mucosa brown-black and, in concentrated form, causes corrosive injury, laryngeal oedema and gastric irritation. Management is supportive with attention to the airway.

Option by option

  • A. Carbolic acid

    Carbolic acid turns the mucosa white and gives a characteristic phenolic smell.

  • B. Potassium permanganate (correct)

    Correct. Brown-black staining with corrosion fits permanganate.

  • C. Copper sulphate

    Copper sulphate gives a blue-green vomit and metallic taste.

  • D. Nitric acid

    Nitric acid stains tissues yellow because of the xanthoproteic reaction.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is B, Potassium permanganate. Potassium permanganate is a strong oxidiser that stains the mucosa brown-black and, in concentrated form, causes corrosive injury, laryngeal oedema and gastric irritation.

Why is "Carbolic acid" not the answer?

Carbolic acid turns the mucosa white and gives a characteristic phenolic smell.

Why is "Copper sulphate" not the answer?

Copper sulphate gives a blue-green vomit and metallic taste.

Why is "Nitric acid" not the answer?

Nitric acid stains tissues yellow because of the xanthoproteic reaction.

What concept does this question test?

It tests Toxicology: potassium permanganate in Forensic Medicine. Management is supportive with attention to the airway.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Toxicology: potassium permanganate?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.