Question

why is potassium Nitrate also called as nitre?
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Answer 1

Answer:

It is a source of nitrogen, and nitrogen was named after niter. Potassium nitrate is one of several nitrogen-containing compounds collectively referred to as saltpetre (or saltpeter in North America).

Answer 2

Answer:

It is an ionic salt of potassium ions K + and nitrate ions NO 3−, and is therefore an alkali metal nitrate. It occurs in nature as a mineral, niter (or nitre in the UK). It is a source of nitrogen, and nitrogen was named after niter.

hope it helps you to understand.