Home > Community > Why are magnesium chloride and calcium chloride more soluble than sodium chloride?
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Mawerere Swaliki

Why are magnesium chloride and calcium chloride more soluble than sodium chloride?

Brian Dean  Follow

$\ce{MgCl2}$ and $\ce{CaCl2}$ are more soluble than $\ce{NaCl}$ because In $\ce{MgCl2}$ and $\ce{CaCl2}$ the ionic charge is +2 hence it can interact with more number of $\ce{H2O}$ molecules, as the number of interactions increases more amount of energy is liberated which is a hydration energy which is sufficient enough to overcome the lattice energy of the compound.Even solubility increases with increase in charge on ion.

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Hans Proebsting  Follow
would show this is not really how solubility is predicted/explained.More
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Ivaylo Stefanov  Follow
solubility chartMore
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Jack Fish  Follow
If only chemistry were so simple… A brief look at the More
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Brian Good  Follow

I don't think there is any simple answer.There are some rules of thumb, all of which have exceptions. Most chlorides are soluble. That includes both MgCl2 and CaCl2.

Solubility is the result of the balance between competing interactions: between the ions in the salt and between those ions and the water.

Many factors contribute to the solubility of a compound in water. In this case, the main difference between the compounds is the bonds’ strength.

The longer answer is to do with something called the "enthalpy of solvation".'

you can think it this way that the lattice enthalpy in MgCl2 and CaCl2 will be less and can be easily be overpowered by hydration enthalpy

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Helmut Bammer  Follow
I am afraid solubility is one of the properties that cannot be properly explained yet. For example why is CaF2 absolutely insoluble ? By comparaison CaCl2, CaBr2 and CaI2 are all extremely soluble in water, as they can be dissolved in less than their weight of water.More
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Jay Hulbert  Follow
Why is lattice enthalpy of MgCl2 is less than NaClMore
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