Reaction of Cu(NO₃)₂ with each salt is as follow,
1) with KNO₃;
Cu(NO₃)₂ + KNO₃ → Cu(NO₃)₂ + KNO₃
Both salt products are water soluble.
2) With CuSO₄;
Cu(NO₃)₂ + CuSO₄ → CuSO₄ + Cu(NO₃)₂
Again both Salt products are water soluble.
3) With K₂SO₄;
Cu(NO₃)₂ + K₂SO₄ → CuSO₄ + 2 KNO₃
Again both salt products are water soluble.
4) With K₂S;
Cu(NO₃)₂ + K₂S → CuS + 2 KNO₃
In this case CuS is water insoluble, hence precipitates out.
Result:
Option-4 is the correct answer.
D.
The products will have at least 2 Na atoms and 1 O atom.
<h3>Further explanation</h3>
If we refer to the law of mass conservation, which states that
<em>In a closed system, the masses before and after the reaction are the same
</em>
then the number of atoms in the reactance will be the same as the number of atoms in the product
In this problem it is known that Na₂O is one of the reactants so that the product of Na atoms and O atoms will at least equal the number of atoms in the bond, namely 2 Na and 1 O
Like an example of this Na₂O reaction:
Na₂O + H₂O ⇒ 2 NaOH
Na : left =2, right = 2
O : left=2, right = 2
I’m assuming your just writing the formula? If so
Potassium chloride: KCL
Potassium nitride: KNO2
Potassium sulfide: K2S
calcium chloride: CaCl2
Calcium nitride: Ca3N2
Calcium sulfide: CaS
Silver chloride: AgCl
Silver nitride: Ag3N
Silver sulfide: Ag2S
Manganese (||) chloride: MnCl2
Manganese (||) nitride: Mn3N2
Manganese (||) sulfide: MnS
Potential energy is the energy stored. What do u think it is? (I don't really know)