Equilibrium: Iron(III) as Indicator for Ag+ Concentration

  • Thread starter Intr3pid
  • Start date
  • Tags
    Equilibrium
In summary, the conversation discusses using Fe as an indicator in a reaction to determine the concentration of an unknown solution of Ag+ by reacting it with a solution of KSCN of known concentration. This is similar to the volhard titration method where the end point is reached when the color disappears.
  • #1
Intr3pid
39
0
hi

I'm really having trouble with this question, can anyone help?

When Ag+ ions re added to the red FeSCN2+ ions, the color disappears, and white precipitate of AgSCn forms. Explain why the Iron(III) can be used aws an indicator in a reaction to determine the concentration of an unknown solution of Ag+ by reacting it with a solution of KSCN of known concentration. (the system is at equilibrium as well)

thanks
 
Physics news on Phys.org
  • #2
When Ag+ ions re added to the red FeSCN2+ ions, the color disappears, and white precipitate of AgSCn forms.

So what is the significance of this as it relates to using Fe as an indicator?
 
  • #3
it's similar to the volhard titration, you titrated the unknown sample with the known standard of KSCN with iron(III) as an indicator, when the color disappears, you've reached the end point.
 

1. What is the purpose of using Iron(III) as an indicator for Ag+ concentration in equilibrium?

The purpose of using Iron(III) as an indicator is to determine the concentration of Ag+ ions in a solution at equilibrium. Iron(III) ions are able to form a complex with Ag+ ions, causing a distinct color change when the equilibrium point is reached. This allows for a visual indication of when the reaction has reached equilibrium.

2. How does the color change of the Iron(III)-Ag+ complex indicate equilibrium?

The color change is a result of the formation of a complex between Iron(III) and Ag+ ions. Before equilibrium, the solution will appear yellow due to the presence of Iron(III) ions. As Ag+ ions are added to the solution, they will begin to react with the Iron(III) ions, forming a red-brown complex. Once the equilibrium point is reached, the color of the solution will stay the same, indicating that no more reactions are occurring.

3. Can Iron(III) be used as an indicator for other metal ions in equilibrium reactions?

Yes, Iron(III) can be used as an indicator for other metal ions in equilibrium reactions. This is because Iron(III) is a Lewis acid and has a high affinity for binding to metal ions, causing a color change when the equilibrium point is reached. However, the specific color change and sensitivity may vary depending on the metal ion being tested.

4. Are there any limitations to using Iron(III) as an indicator for Ag+ concentration in equilibrium?

Yes, there are some limitations to using Iron(III) as an indicator. One limitation is that the color change may not be very sensitive, making it difficult to determine the exact equilibrium point. Additionally, the presence of other ions in the solution may interfere with the formation of the Iron(III)-Ag+ complex, leading to inaccurate results.

5. How can the accuracy of using Iron(III) as an indicator for Ag+ concentration in equilibrium be improved?

To improve the accuracy of using Iron(III) as an indicator, it is important to carefully control the experimental conditions and minimize the presence of interfering ions. This can be done by using a high purity sample, adjusting the pH of the solution, and conducting multiple trials to ensure consistent results. Additionally, using a spectrophotometer to measure the absorbance of the complex can provide a more precise determination of the equilibrium point.

Similar threads

How Does Le Chatelier's Principle Affect Silver Dissolution in This Reaction?
    • Biology and Chemistry Homework Help
Replies
7
Views
2K
Change in concentration in equilibrium caused by addition
    • Biology and Chemistry Homework Help
Replies
8
Views
1K
Explaining The Non-Reaction Of An Iron Nail With Equilibrium
    • Biology and Chemistry Homework Help
Replies
7
Views
2K
Determining Cl- and Ag+ Concentrations in A Solution
    • Biology and Chemistry Homework Help
Replies
1
Views
1K
Precipitation of lead hydroxide in the presence of EDTA
    • Biology and Chemistry Homework Help
Replies
5
Views
1K
Calculating Absorbance of Iron (III) Solution at 580nm for 2.50-cm Cell
    • Biology and Chemistry Homework Help
Replies
2
Views
6K
Precipitation of Metal Chlorides
    • Biology and Chemistry Homework Help
Replies
4
Views
2K
Equilibrium chem lab (FeSCN2+)
    • Biology and Chemistry Homework Help
Replies
1
Views
7K
Determine percentage of iron(II) and iron(III) in a solution
    • Biology and Chemistry Homework Help
Replies
13
Views
5K
What are some experimental errors associated with spectrophotommetry?
    • Biology and Chemistry Homework Help
Replies
1
Views
3K

Hot Threads

Recent Insights

Back
Top