Toxicology: mineral acids: 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: mineral acids

Sample item

A man presents after drinking an acid. The lips and chin show yellow stains and the oral mucosa appears yellow and leathery. Which acid is most likely?

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

The answer and the reasoning

A. Nitric acid

Nitric acid reacts with proteins to give a yellow xanthoproteic stain. Sulphuric acid causes black charring and severe dehydration, hydrochloric acid gives greyish-brown stains, and oxalic acid produces hypocalcaemia and renal damage.

Option by option

  • A. Nitric acid (correct)

    Yellow xanthoproteic staining is typical of nitric acid.

  • B. Sulphuric acid

    Sulphuric acid produces black charred tissue.

  • C. Oxalic acid

    Oxalic acid is an organic acid causing hypocalcaemia and crystalluria.

  • D. Hydrochloric acid

    Hydrochloric acid produces greyish-brown corrosion.

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 A, Nitric acid. Nitric acid reacts with proteins to give a yellow xanthoproteic stain.

Why is "Sulphuric acid" not the answer?

Sulphuric acid produces black charred tissue.

Why is "Oxalic acid" not the answer?

Oxalic acid is an organic acid causing hypocalcaemia and crystalluria.

Why is "Hydrochloric acid" not the answer?

Hydrochloric acid produces greyish-brown corrosion.

What concept does this question test?

It tests Toxicology: mineral acids in Forensic Medicine. Sulphuric acid causes black charring and severe dehydration, hydrochloric acid gives greyish-brown stains, and oxalic acid produces hypocalcaemia and renal damage.

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: mineral acids?

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.