Question

Determine the total number of moles of ions in 40.0 ml of a 0.345 m solution of the strong electrolyte mgcl2

Answer 1

A strong electrolyte like MgCl2 dissociates completely as per the following reaction:

$MgCl_2 ----\ \textgreater \ Mg^{2+} + 2Cl^-$

As you can see, from 1 molecule of MgCl2 produces 3 ions on dissociation.
So, 1 mole of MgCl2 produces 3 moles of ions.

Now, Moles of MgCl2 = Volume x Molarity

= 0.04 x 0.345   [Change volume to Litres]
= 0.0138 moles

Now, total moles of ions =  0.0138 x 3 = 0.0414