Answer: 1758
Notes: British East India Company secured the monopoly of saltpetre trade in Bihar in 1758. Saltpeter is also called as Potassium nitrate. It is an ionic salt of potassium ions and nitrate ions and is therefore an alkali metal nitrate. It occurs in nature as a mineral, niter. It is a source of nitrogen, and nitrogen was named after niter. Saltpetre was one of the major trade goods of the British East India Comoany. Britishers used saltpetre for gunpowder.
