Iron(III) Hydroxide Precipitation
FeCl3 + 3NaOH → Fe(OH)3↓ + 3NaCl
Overview
Iron(III) chloride reacts with sodium hydroxide to form a rust-brown gelatinous precipitate of iron(III) hydroxide. Fe(OH)₃ has an extremely low Ksp of 2.8 × 10⁻³⁹, precipitating even at slightly acidic pH. The gelatinous nature makes it an excellent flocculant for water treatment.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Iron(III) Chloride FeCl₃ | 1 | (aq) |
| Reactant | Sodium Hydroxide NaOH | 3 | (aq) |
| Product | Sodium Chloride NaCl | 3 | (aq) |
Everyday Example
The rust-colored sludge in water treatment plants is mainly iron(III) hydroxide precipitated by adding base to iron-rich water.
Industrial Importance
Iron(III) hydroxide precipitation is the primary method for iron removal from drinking water and is used as a coagulant in wastewater treatment.
Properties
- Type
- Precipitation
- Reversible
- No
- Energy
- Exothermic
- ΔH
- -88.0 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 Iron(III) Hydroxide Precipitation?
The balanced equation is: FeCl₃ + 3NaOH → Fe(OH)₃↓ + 3NaCl.
What type of reaction is Iron(III) Hydroxide Precipitation?
Iron(III) Hydroxide Precipitation is a precipitation reaction.
Is Iron(III) Hydroxide Precipitation exothermic or endothermic?
Iron(III) Hydroxide Precipitation is exothermic (releases energy). The enthalpy change (ΔH) is -88.0 kJ/mol.