pure
Generally rock salt is more impure than table salt.
Any chemical may be pure or impure.
Pure
impure
Pure water does not contain colour but impure water contains Other compounds.
Generally an impure material is cheaper than a pure material; the word advantage is not so adequate here - can use pure or impure, this depends on the specific applications.
The suitable prefix for pure is pure it won't make sense of you put another set of words in front of pure it just would not make
impure
mixture
yes it is true that arteries contain pure blood and veins contain impure blood
If there is no salt or substance that makes it impure it is a pure mixture
Yes Baking Powder Is A Pure Substance.