Ionisation vs Dissociation

Question

This is a statement given in my book:

A strong electrolyte is completely ionised at all dilutions but not completely dissociated.

But the book also uses the terms "Ionisation" and "Dissociation" interchangeably in other places.

When I further tried to search about this topic I found out there is equation which governs dilution of strong electrolyte-

$\lambda_m = \lambda_o + a\sqrt C$

So is it right to say that it will only get completely dissociated at infinite dilution (which is not practically possible)?

Hence my final questions are:

1. Are ionisation and dissociation the same or different?

2. If they are not the same then why are they different?

3. Also the correct explanation of the above statement given in my book?

4. Will this change for a weak electrolyte?

Also please consider that I am in high school. So please try to explain in simple terms so that I am able to clear my confusion.

Please also tell whether I can assume both the terms to be same or not at my current high school level.

Answer 1

The parameter a in front of √C is empirical. It varies from solute to solute.

And yes, the dissociation is complete at infinite dilution.

Dissociation is the separation of ions when dissolving a salt in water. If NaCl is dissociated, it yields two independent ions, one Na+ and one Cl−

Ionization is what happens when an atom or a molecule looses one electron, without being modified or broken. If $\ce{NaCl}$ is dissociated, it gives two independent ions, one $\ce{Na+}$ and one $\ce{Cl−}$ If $\ce{H2O}$ is ionized, it gives an ion $\ce{H2O}$+ and one electron, but the atoms of the molecule are not separated from one another.