In testing the relative stabilities of Cu(II) species using a well plate, a
student adds 6 drops \(1 \mathrm{M} \mathrm{NH}_{3}\) to
6 drops 0.1 \(\mathrm{M} \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}\). He
observes that a blue precipitate initially forms, but that in excess
\(\mathrm{NH}_{3}\) the precipitate dissolves and the solution turns blue.
Addition of 6 drops \(1 \mathrm{M} \mathrm{NaOH}\) to the dark-blue solution
results in the formation of a blue precipitate.
a. What is the formula of Cu(II) species in the dark-blue solution?
b. What is the formula of the blue precipitate present after addition of \(1
\mathrm{M} \mathrm{NaOH} ?\)
c. Which species is more stable in equal concentrations of \(\mathrm{NH}_{3}\)
and \(\mathrm{OH}^{-}\), the one in Part a or the one in Part b?
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