FeCl2 + NaOH = Fe(OH)2 + NaCl Reaction
Aqueous ferrous chloride (FeCl2) reacts with aqueous sodium hydroxide NaOH to produce ferrous hydroxide Fe(OH)2 and sodium chloride (NaCl). Color changes, precipitating, balanced reaction, ionic equation of FeCl2 + NaOH reaction are discussed in this tutorial.
written by: Heshan Nipuna, updated on: 26/05/2020
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Aqueous ferrous chloride and aqueous sodium hydroxide reaction
Ferrous chloride ( Iron(II) chloride ) is a soluble inorganic compound in water and form a pale green color solution.
Sodium hydroxide is a strong alkaline colorless solution.
What are the products when aqueous ferrous chloride reacts with aqueous sodium hydroxide
When we add aqueous NaOH solution to aqueous FeCl2 solution, green color precipitate is formed. This precipitate is ferrous hydroxide ( Fe(OH)2 ).
FeCl2 + NaOH = Fe(OH)2 + NaCl
Above reaction is not a balanced chemical reaction. Therefore, you need to balance this reaction and we will do it in next section.
How to balance FeCl2 and NaOH reaction?
This reaction is a not a redox reaction. Therefore by observing number of atoms in right side and left side, we can balance the reaction in few seconds.
Balanced reaction of FeCl2 and NaOH
FeCl2 + 2NaOH = Fe(OH)2 + 2NaCl
According to the stoichiometry of the reaction, 1 mol of FeCl2 reacts with 2 mol of NaOH and produce 1 mol of Fe(OH)2 and 2 mol of NaCl.
Balanced reaction of FeCl2 and NaOH with physical states
FeCl2(aq) + 2NaOH(aq) = Fe(OH)2(s) + 2NaCl(aq)
Solubility of Fe(OH)2 is poor in water. Hence it deposits as a precipitate.
What will happen if Fe(OH)2 is exposed to air?
Fe(OH)2 is easily oxidized to Fe(OH)3 by oxygen gas. Therefore, green color of the precipitate will be changed to reddish brown when Fe(OH)3 is formed.
Questions asked by students
Ask your question and find the answer free.
If small voloume of low concentratrated NaOH is added to FeCl2 solution, will it give a precipitate?
Whether NaOH concentration is low, if ferrous ion concentration is high, Fe(OH)2 precipitate will be formed due to having enough concentrations of ions to exceed solubility product.
Write the ionic equation of forming Fe(OH)2, from NaOH and FeCl2
Fe2+ + OH- → Fe(OH)2
If FeCl2 + NaOH gives Fe(OH)2 pricipitate, will it dissove in excess NaOH?
Fe(OH)2 is not soluble in excess NaOH or aqueous ammonia solution.
What are the other ferrous +2 compound which can be used to prepare Fe(OH)2 with NaOH?
If we can give Fe2+ ion to the NaOH solution, Fe(OH)2 precipitate can be formed. To give Fe2+ ions, soluble Fe2+ compound should be used. Therefore, FeSO4, Fe(NO3)2 can be used as compounds. FeCO3 cannot be used because it is insoluble in water and gives very low Fe2+ ion concentration too.
After few days of adding aqueous NaOH to aqueous FeCl2, I saw a brown color precipitate. Why was happened to green color was at their beginning?
In the presence of oxygen gas, Fe2+ ions readily oxidizes to Fe3+ ions. That's why green color of Fe(OH)2 is tuned to brown color of Fe(OH)3.
How do I prepare Fe(OH)2 precipitate when ferrous, chlorine and aqueous sodium hydroxide are provided as raw materials?
This is not a single step work. You have to do some reactions.
- Solid ferrous metal reacts with chlorine gas to produce solid ferric chloride.
- Add ferric chloride to water. Then, again add some ferrous to that aqueous solution to react with ferric chloride. This will give ferrous chloride.
- Then, add sodium hydroxide solution to ferrous chloride solution.