Which is called Indian Saltpeter

Answer: Potassium nitrate is referred to as Indian Saltpeter. The reason behind this is potassium nitrate includes nitrogen and is crucial as an option for crude salt in the country. Many refer to this compound as niter. 

The chemical formula of the Indian Saltpeter is KNO3. It is basically potassium’s ionic salt. This compound remains in a solid-state and appears to be black. 

It finds use as a raw component for gunpowder. Also, the compound is used by farmers as fertilizer because it gives the plants oxygen and nitrogen, two essential macronutrients.