The chemical formula for nicotine sulfate is C10H14N2.H2SO4. This formula represents the combination of nicotine, a nitrogen-containing organic compound, with sulfuric acid to form a soluble salt. In this formula, "C10H14N2" represents the molecular formula of nicotine, and "H2SO4" represents the formula of sulfuric acid. When these two compounds react, the hydrogen ions (H+) from the sulfuric acid combine with the nitrogen-containing groups of nicotine, resulting in the formation of the nicotine sulfate salt. This salt is commonly used as an insecticide in agriculture due to its ability to disrupt the nervous system of pests, leading to paralysis and eventual death.