Is saltpeter renewable or non-renewable

Answer 1

Renewable means it comes back after it is 'used', like water or sunlight, or it can be grown again, like pine trees.

Saltpeter (potassium nitrate) is non-renewable.

Answer 2

Salt is classed as renewable, because there is always more in the sea, and the sea is always being topped up with minerals washed down by the rivers.