# In a 2.5 M CaCl_2 solution, what is the molarity of the calcium ions?

Sep 9, 2017

AS the name says on the tin, the molarity of calcium ion is $2.5 \cdot m o l \cdot {L}^{-} 1$....

#### Explanation:

And in one litre of solution there are $1 \cdot L \times 2.5 \cdot m o l \cdot {L}^{-} 1 \times 6.022 \times {10}^{23} \cdot m o {l}^{-} 1$ individual calcium ions.....What is the concentration of chloride ions?

Sep 9, 2017

$2.5 M$
Molarity is defined as the number of moles in a liter. If the solution is $2.5 M$, the molarity of the elements is the same basic amount, modified by the number of atoms of each element in the original compound.
In this case, we have one $C a$ atom and two $C l$ atoms in the compound. So, we will have $2.5 M C {a}^{+ 2}$ and $2.5 \times 2 = 5 M C {l}^{- 1}$ ions in solution.