Cobalt(II) Hydroxide Precipitation
CoCl2 + 2NaOH → Co(OH)2↓ + 2NaCl
Overview
Cobalt(II) chloride reacts with NaOH to form a blue or pink precipitate of cobalt(II) hydroxide (Ksp = 5.9 × 10⁻¹⁶). The initial blue precipitate converts to pink upon standing as the crystal structure rearranges. In air, it slowly oxidizes to brown Co(OH)₃.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Sodium Hydroxide NaOH | 2 | (aq) |
| Product | Sodium Chloride NaCl | 2 | (aq) |
Everyday Example
Cobalt chloride paper changes from blue (dry) to pink (wet) and is used as a humidity indicator in weather instruments.
Industrial Importance
Cobalt hydroxide is a precursor for lithium cobalt oxide cathodes in lithium-ion batteries used in smartphones and electric vehicles.
Properties
- Type
- Precipitation
- Reversible
- No
- Energy
- Exothermic
- ΔH
- -52.0 kJ/mol
Related Reactions
Aluminum Hydroxide Precipitation
Barium Carbonate Precipitation
Barium Sulfate Precipitation
Cadmium Sulfide Precipitation (Yellow)
Calcium Carbonate Precipitation
Calcium Fluoride Precipitation (Fluorite)
Calcium Oxalate Precipitation (Kidney Stones)
Calcium Phosphate Precipitation (Bone Mineral)
Calcium Sulfate Precipitation (Gypsum)
Chromium(III) Hydroxide Precipitation
Frequently Asked Questions
What is the equation for Cobalt(II) Hydroxide Precipitation?
The balanced equation is: CoCl₂ + 2NaOH → Co(OH)₂↓ + 2NaCl.
What type of reaction is Cobalt(II) Hydroxide Precipitation?
Cobalt(II) Hydroxide Precipitation is a precipitation reaction.
Is Cobalt(II) Hydroxide Precipitation exothermic or endothermic?
Cobalt(II) Hydroxide Precipitation is exothermic (releases energy). The enthalpy change (ΔH) is -52.0 kJ/mol.