After equal volumes of Na$$_{2}$$S and CuSO$$_{4}$$ were mixed, what happened to the supernatant upon the addition of the test solution, and what does that indicate?
The solution turned dark blue, indicating that CuSO$$_{4}$$ was the excess reactant.
A precipitate formed, indicating that Na$$_{2}$$S was the excess reactant.
A precipitate formed, indicating that CuSO$$_{4}$$ was the excess reactant.
The solution remained colorless without a precipitate forming, indicating that neither reagent was in excess.