Previous Year Question
Which of the following acids is present in the stinging hairs of Nettle leaves?
Correct Answer: B
Detailed Solution
According to NCERT, the stinging hairs present on Nettle leaves secrete methanoic acid, which causes burning pain and irritation when the plant is touched. NCERT's table of naturally occurring acids also lists Nettle sting — Methanoic acid.
However, there is an important error in this question. Option B) Methanoic Acid and option C) Formic Acid are actually two names for the same chemical substance.
Methanoic acid = Formic acid = HCOOH
Therefore, scientifically, both B and C represent the same answer. The answer key gives B because NCERT uses the name “Methanoic acid” in this context, but presenting Formic acid as a separate alternative is incorrect.
Thus, the expected examination answer is B) Methanoic Acid, but the question contains duplicate correct options.