Question

The following salts are arranged in order of increasing lattice energy, what is your expectation about arranging them in order of increasing the solubility in water! Why! AlCl3>MgCl2>KCl>NaCl ←------------------------------ Increasing of lattice energy

Answer 1

AlCl3 < MgCl2 < KCl < NaCl

Lattice energy will be required for disassociation of 1 mole of an ionic compound into its ions.  

In this way, higher will be lattice energy , more will be required to change an ionic compound into its ion and consequently will be least soluble.

Answer 2

Answer:

: AlCl_3AlCl

3

<MgCl_2MgCl

2

<KClKCl <NaClNaCl

Explanation: Lattice energy is the energy required to dissociate 1 mole of the an ionic compound into its constituent ions.

Thus higher is the lattice energy more energy will be required to convert the ionic compounds into its ions and hence will be least soluble.

As AlCl_3AlCl

3

has highest lattice energy, it will require most energy to dissociate into ions an hence it will be least soluble in water. The order of solubilities will follow the reverse order to that of lattice energies.

AlCl_3AlCl

3

<MgCl_2MgCl

2

<KClKCl <NaClNaCl