2021 · Q24
Which one of the following acids is secreted by leaves of Nettle that causes painful stings?
General KnowledgeChemistry
- AMethanoic acid
- BCitric acid
- CTartaric acid
- DAcetic acid
Explanation
The stinging hairs of nettle (Urtica) leaves inject methanoic acid - formic acid - together with histamine, producing the painful sting. Citric, tartaric and acetic acids are not secreted by nettle leaves for this purpose.