Question

nettle sting is the natural source of which acid

Answer 1

Answer:formic acid

Nettle stings contain acid (formic acid) but they also contain histamine and other chemicals. The exact details are still unknown but it is the histamine that causes the initial reaction when you are stung. Dock leaf sap contains a natural antihistamine, which helps to ease the stinging sensation.

Answer 2

$\mathcal\blue{Formic\:Acid(HCOOH)}$

$\mathcal\red{Or}$

$\mathcal\blue{Methanoic\:Acid}$