Preparation of Ferric Hydroxide Sol

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Preparing Ferric Hydroxide Solution

Here, we discuss a step-by-step procedure for conducting an experiment to help you learn how to prepare ferric hydroxide sol. To understand the goal, procedure, and materials required to perform the experiment, go through the content carefully.


The aim of this experiment – to prepare ferric hydroxide sol.


A lyophobic sol is formed by ferric hydroxide. Lyophobic colloids are called compounds such as metal hydroxides or sulfides that are insoluble and do not readily have colloidal solutions for treatment with water. Ferric hydroxide sol is prepared with boiling distilled water by hydrolysis of ferric chloride.

The reaction for preparation of Fe(OH)3 sol is given below

FeCl3(aq) + 3H2O(l)→ Fe(OH)3(s) +3HCl(aq)

The hydrolysis reaction creates insoluble particles of ferric hydroxide that are agglomerated to create larger colloidal-dimensional particles. To give a positive charge to the soln particles, these particles preferentially adsorb Fe3+ ions from the solution. The Soln's stability is due to the charge on the particles of the solution. Hydrochloric acid formed during hydrolysis tends to destabilize the sol and must therefore be extracted by the dialysis process from the sol, or the sol would not be stable.

Materials Required

The apparatus and materials required for this experiment are as follows:

  1. Glass rod

  2. Round bottom flask

  3. Boiling tube

  4. Conical flask of 250 mL volume

  5. Tripod stand

  6. Funnel

  7. Beaker of 250 mL volume

  8. Burette

  9. Wire gauze

  10. Dropper

  11. Burner

  12. Wire gauze

  13. Iron stand with clamp

  14. Boiling tube

  15. Distilled water

  16. The solution of ferric chloride


  1. Take a 250 mL conical flask and clean it with steam.

  2. Take the aid of the following figure to clean the conical flask by steaming out the process.

(Image will be uploaded soon)

  1. By taking 2 g of pure ferric chloride in 100 mL of distilled water, prepare a 2% solution of ferric chloride.

  2. Take the cleaned conical flask and add 100 mL of distilled water by steaming out the process.

  3. On a wire gauze, boil the bath.

  4. Drop by drop, with the aid of a dropper or desk, pour 10 mL of ferric chloride solution.

  5. Keep stirring the mixture of boiling water continuously when adding ferric chloride solution.

  6. Until you see a brown or deep red ferric hydroxide solution, heat the conical flask containing a combination of distilled water and ferric chloride solution.

  7. Enable the mixture to settle at room tempurature in the conical flask.


  1. Due to the presence of impurities, Fe(OH)3 sol is impaired. Therefore, it is washed by steaming out a method to stop this conical flask.

  2. It is applied drop-wise to the FeCl3 solution.

  3. Heat the distilled water and ferric chloride solution mixture until the colour is brown or deep red.

  4. To avoid solar destabilization, the hydrochloric acid (HCl) produced is removed by the dialysis process.

Applications of Ferric Hydroxide

In the construction industry, ferrous hydroxide products such as yellow iron oxide/iron (III) oxide hydroxide are commonly used to produce concrete products such as bricks, blocks, decorative concrete, paving stones, ready-mixed concrete, and roofing tiles. A significant contributor to the growth of residential construction is a growing population in developing countries.

Did You Know?

The rapid expansion of the construction sector would fuel the growth of the demand for ferric hydroxide. Many regional/local players sell their goods across creative distribution channels to the construction industry. On the back of the expanding construction industry in India and China, the ferrous hydroxide market in the Asia Pacific region is expected to see substantial growth.

The global ferric hydroxide market is expected to hit the US$1 billion mark by the end of 2029, with a CAGR of 5% during 2019-2029 for healthy growth. Market geographical research shows that East Asia and North America will continue to capture about 50 percent of the global ferric hydroxide market's revenue share.

FAQ (Frequently Asked Questions)

Q1. Is Ferric Hydroxide a Strong Base?

Ans. The theory of Arrhenius, presented in 1887 by the Swedish scientist Svante Arrhenius, is that acids are substances that dissociate in water to create electrically charged atoms or molecules, called ions, one of which is a hydrogen ion (H+), and that base ionizes in water to produce hydroxide ions (OH-). For example, acetic acid (HC2H3O2) and oxalic acid (H2C2O4) are weak acids, while examples of weak bases include iron hydroxide, Fe(OH)3, and ammonium hydroxide, NH4OH (which in reality is only ammonia, NH3, dissolved in water).

Q2. Is Iron Hydroxide an Alkali?

Ans. Alkalis are called bases that are soluble in water. But bases like Cu(OH)2, ferric hydroxide (Fe(OH)3), aluminium hydroxide (Al(OH)3) copper hydroxide do not dissolve in water. They are, consequently, not alkalis. Both alkalis are, thus, bases, but not all bases are alkalis.

Q3. Why is Ferric Hydroxide Sol Positively Charged?

Ans. A lyophobic sol is formed by ferric hydroxide. To give a positive charge to the soln particles, these particles preferentially adsorb Fe3+ ions from the solution. The colloidal particles in ferric hydroxide, therefore, carry a positive charge, and therefore the solution of ferric hydroxide is positively charged.