when acidified potassium dichromate (VI) is added to iron(II) sulfate why does a redox reaction occur?
How about if ammonia is added to iron(II) sulfate?
The dichromate is oxidized, so it needs H+ ions in solution to form water.
One the second "question", I miss your question; are you referring to Mohr's Salt? I really don't know what you are asking.
When acidified potassium dichromate (VI) is added to iron(II) sulfate, a redox reaction occurs because of the transfer of electrons between the reactants. In this reaction, iron(II) sulfate acts as the reducing agent, while potassium dichromate (VI) acts as the oxidizing agent.
The iron(II) ions in iron(II) sulfate are oxidized to iron(III) ions by transferring two electrons to the chromium(VI) ions in potassium dichromate. This reduction of chromium(VI) to chromium(III) results in the formation of green chromium(III) sulfate.
The overall balanced equation for this reaction is:
3Fe^2+ (aq) + Cr2O7^2- (aq) + 14H^+ (aq) → 3Fe^3+ (aq) + 2Cr^3+ (aq) + 7H2O (l)
Now, let's consider the reaction between ammonia and iron(II) sulfate. Ammonia (NH3) is a weak base, and it can react with iron(II) ions to form a complex compound called tetraammineiron(II) ion.
In the presence of excess ammonia, the reaction between iron(II) sulfate and ammonia proceeds as follows:
Fe^2+ (aq) + 6NH3 (aq) → [Fe(NH3)6]^2+ (aq)
The reaction results in the formation of a pale green complex with six ammonia molecules coordinated around the iron(II) ion.
The balanced equation for this reaction is:
Fe^2+ (aq) + 6NH3 (aq) → [Fe(NH3)6]^2+ (aq)
Overall, the addition of ammonia to iron(II) sulfate does not involve a redox reaction but rather a coordination complex formation.
When you add acidified potassium dichromate (VI) to iron(II) sulfate, a redox reaction occurs because there is a transfer of electrons between the reactants. Let's break down the reaction and understand the process step by step:
1. Initially, we have iron(II) sulfate, which can be represented as FeSO4. The iron ion in FeSO4 has a +2 charge.
2. Acidified potassium dichromate (VI) is represented as K2Cr2O7. In this compound, the chromium ion has a +6 charge.
3. When we mix the two substances, the Fe2+ ion in FeSO4 can easily lose two electrons to the Cr6+ ion in K2Cr2O7. This results in the formation of Fe3+ ions and Cr3+ ions.
The overall balanced equation for this redox reaction is:
6Fe2+ + Cr2O7^2- + 14H+ -> 6Fe3+ + 2Cr3+ + 7H2O
In this reaction, iron(II) ions (Fe2+) are oxidized to iron(III) ions (Fe3+), with the chromium(VI) ions (Cr2O7^2-) acting as the oxidizing agent. The chromium(VI) ions are reduced to chromium(III) ions (Cr3+) and water (H2O) is produced as a byproduct.
Now, let's consider what happens when ammonia (NH3) is added to iron(II) sulfate (FeSO4). No redox reaction occurs in this case. Instead, coordination complexes are formed between ammonia and iron(II) ions:
1. The ammonia (NH3) molecules coordinate with the iron(II) ions (Fe2+) to form [Fe(NH3)6]2+ complex ions. In this complex, six ammonia molecules surround each iron(II) ion.
The balanced chemical equation for this reaction is:
FeSO4 + 6NH3 -> [Fe(NH3)6]SO4
In this reaction, ammonia acts as a ligand, meaning it donates a pair of electrons to the iron ion, forming coordinate bonds. The resulting complex ion is soluble in water and has a different appearance compared to the original iron(II) sulfate solution.