Question

how can you tell a Cu(No3)2 solution from a Ni(NO3)2 solution?

Answer 1

Answer: $Cu(NO_3)_2$ solution has blue color and $Ni(NO_3)_2$ solution has bright green color.

Explanation:

$Cu(NO_3)_2(aq)\rightarrow Cu^{2+}(aq)(blue)+ NO_{3}^{1-}(aq)$

$Cu(NO_3)2$ in its aqueous solution gives blue color solution. Copper being transition metal and gives characteristic color in their in aqueous solution.

$Ni(NO_3)_2(aq)\rightarrow Ni^{2+}(aq)(green)+ NO_{3}^{1-}(aq)$

$Ni(NO_3)2$ in its aqueous solution gives bright green color solution. Nickel is also a transition metal and gives characteristic color in their in aqueous solution.