Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. It only takes a minute to sign up.
Sign up to join this community
Applying what's been said in the Wikipedia page for equivalents, if $1\ \mathrm{mol}$ of $\ce{NaCl}$ and $1\ \mathrm{mol}$ of $\ce{CaCl2}$ are dissolved in a solution, there is $\rm1~eq~Na,~2~eq~Ca$, and $\rm3~eq~Cl$ in that solution.
Is this a misstatement in Wikipedia?
The Wikipedia article uses a funny defintion of equivalent that I have not heard yet even though I use the term extremely frequently in the lab. But they define it well so here goes:
One equivalent of ions is defined as $1~\mathrm{mol}$ of charge. So if we dissolve $1~\mathrm{mol}$ of $\ce{Na+}$, we have exactly $1~\mathrm{mol}$ of positive charges in solution, so $1~\mathrm{mol} \cdot 1~e = 1~\mathrm{eq}$ ($e$ being the elemental charge). The $1~\mathrm{mol}$ of $\ce{Cl-}$ contributes $1~\mathrm{eq}$ of negative charges, balancing the entire thing.
Calcium, however, has a $\mathrm{+II}$ oxidation state. So $1~\mathrm{mol}$ of $\ce{Ca^2+}$ gives us $1~\mathrm{mol} \cdot 2~e = 2~\mathrm{eq}$ of positive charge.
The link in the original post may refer to the equivalent of the number or ratio of electrons shared by each of the specific ions, according to their chemical formula, in the solution, rather than the ratio of specific ions that are present in the solution.
No the statement is absolutely correct. We can write number of equivalents = Weight of the metal/ its equivalent weight. Since the equivalent weight of calcium in CaCl2 is 20 gm hence we get the number of equivalents of Ca as 2.
