Explanation:
Chemical equation for the given reaction is as follows.
[tex][Co(H_{2}O)_{6}]^{2} + 4Cl^{-} \rightleftharpoons [CoCl_{4}]^{2-} + 6H_{2}O[/tex]
First, we will calculate the moles of [tex]Co^{2+}[/tex] as follows.
[tex]\frac{0.652 \times 1 mole Co^{2+}}{1 mole [CoCl(H_{2}O)_{6}]^{2+}}[/tex]
= 0.652 mol [tex]Co^{2+}[/tex]
Therefore,
[tex]\frac{0.129 \times 1 mole Co^{2+}}{1 mol of CoCl^{2-}_{4}}[/tex]
= 0.129 moles of [tex]Co^{2+}[/tex]
Now, moles per liter of [tex]Co^{2+}[/tex] which will not react will be calculated as follows.
0.652 - 0.129
= 0.523
Thus, we can conclude that there are 0.523 moles of [tex]Co^{2+}[/tex]present per liter.
