Question

The solid anhydrous solid CoCl2 is blue in color. Because it readily absorbs water from the air, it is used as a humidity indicator to monitor if equipment (such as a cell phone) has been exposed to excessive levels of moisture. Predict what product is formed by this reaction, and how many unpaired electrons this complex will have.

Answer 1

`CoCl_(2).(H_(2)O)_(6)` is formed and it has three unpaired electrons.

Step-by-step explanation:

Blue
`CoCl_(2)` reacts with water to produce pink colored
`CoCl_(2).(H_(2)O)_(6)` complex.

In this complex,
`Co^(2+)` ion forms an octahedral complex with six
`H_(2)O` ligands.

As
`H_(2)O` is a weak field ligand therefore
`Co^(2+)` ion remains in low spin state.

Hence electronic configuration of
`Co^(2+)` ion in this octahedral geometry is
`t_(2g)^(5)e_(g)^(2)` with total three unpaired electrons.