# Why are there 2 equivalents of Ca in an example stated in Wikipedia?

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.

• Sir I meant this only in my answer. Actually it's not funny but we see equivalent as the number of eq. electrons bringing out the reactions. I did not write this because it might have confused the asker. – Akshay Pratap Singh Feb 12 '16 at 3:16
• You see we have 2e = Weight of metal/ its equivalent weight( from electro-chemistry). – Akshay Pratap Singh Feb 12 '16 at 3:19
• @AkshayPratapSingh There is no need to comment on an unrelated answer to answer to a comment I gave under your answer. Instead, comment in the same spot and ping me with @ followed by the username. – Jan Feb 13 '16 at 17:43

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.

• Reread the Wikipedia article, please. – Jan Feb 12 '16 at 1:13