Answer: The order of increasing lattice energy is 
Explanation: Lattice energy is defined as the energy required to break the intermolecular force that is responsible for the formation of a lattice.
Melting point is defined as the temperature at which solid gets converted into liquid due to the weakening of the bonds in the solid form.
- Relation between lattice energy and Melting point:
The relationship between these two is direct.

More the melting point of a compound, more will be its lattice energy.
Order of increasing Lattice energy will be:

Answer:
- Addition of Ba(OH)2: favors the formation of a precipitate.
- Undergo a chemical reaction forming soluble species.
- Addition of CuSO4 : favors the formation of a precipitate.
Explanation:
Hello,
In this case, since the dissociation reaction of barium sulfate is:

We must analyze the effect of the common ion:
- By adding barium hydroxide, more barium ions will be added to the equilibrium system so the formation of solid barium sulfate will be favored (reaction shifts leftwards towards reactants).
- By adding sodium nitrate, the following reaction will undergo:

So the precipitate will turn into other soluble species.
- By adding copper (II) sulfate, more sulfate ions will be added to the equilibrium system so the formation of solid barium sulfate will be favored (reaction shifts leftwards towards reactants).
All of this is supported by the Le Chatelier's principle.
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Answer:

Explanation:
Hello.
In this case, for the reaction between aqueous solutions of ammonium chloride and iron (III) hydroxide, we have the following complete molecular reaction:

And the full ionic equation, taking into account that the iron (III) hydroxide cannot be dissolved as it is insoluble in water:

Finally, the net ionic equation, considering that spectator ions are NH₄⁺, Cl⁻ as they are both the left and right side, therefore, the net ionic equation is:

Best regards.
Substances that cannot be separated and found on a periodic table are elements.