Describe the procedure you would follow to determine the concentration of vitamin c in a sample if the volume of dcpip required to reach the end point were more than the 10-mL graduated cylinder could hold. The titration must still be carried out in the 10-mL graduated cylinder. Be sure to include any calculations that you would need to perform.

->I searched this problem up, but I wasn't satisfied with the answers because I didn't understand why (one of the answers talks about using an aliquot, but I don't know how an aliquot would be used in this type of problem)
-> This is from a lab called: "Vitamin c in fruit juices by redox titration"

And you haven't come close to providing enough information for us to know what the problem is.

Sorry... I don't know what information to provide you... I thought the problem was just asking "what must one need to do in order to carry out the titration although the endpoint reaches a volume more than the 10-mL graduated cylinder can hold." I have data with me that I collected through my experiment, and I made an equation with it which is y=2.38x+0.1

->I really don't understand this problem... please if you do have any info or ways to solve it I would be glad with it. The biggest hurdle for me on this question is how would one carry out the experiment knowing that the endpoint would not be reached without having the graduated cylinder overflow.

One thing you could have done is to provide the possible answers. An aliquot is the way to go.

Without knowing the details I can only generalize. What you want to do is to take an aliquot of the sample. Apparently you are titrating into a 10 mL graduated cylinder, or at least a container with that volume. So using a smaller volume will require less titrant to be used. What is the volume you are titrating? Something like 5 mL. Then take 1 mL and titrate that. Whatever volume is used to titrate the 1 mL sample is multiplied by 5 to know what the full sample would have required and you go from there.

DrBob222 thank you so much! you don't know how much I was struggling. The information is enough for me :)

To determine the concentration of vitamin C in a sample using a redox titration with 2,6-dichlorophenolindophenol (DCPIP) in a 10-mL graduated cylinder, you can follow the procedure outlined below:

1. Prepare a standard solution of vitamin C: Start by preparing a known concentration of vitamin C solution. This can be achieved by dissolving a known mass of pure vitamin C (ascorbic acid) in a known volume of water.

2. Perform a titration: Measure 10 mL of the standard vitamin C solution using the graduated cylinder and transfer it into a clean conical flask. Add a few drops of DCPIP indicator to the flask. DCPIP is a blue dye that turns colorless upon reduction. Note that if the volume of DCPIP required to reach the endpoint is more than what the graduated cylinder can hold, you need to perform the titration in several steps.

3. Initial titration: Using a transfer pipette or a syringe, add a small volume (e.g., 1 mL) of the solution of DCPIP into the conical flask containing the standard vitamin C solution. Swirl the flask to mix the contents.

4. Analyze the color change: The DCPIP solution will initially turn blue. As you slowly add more of the DCPIP solution, the blue color will start to fade. Add the DCPIP solution drop by drop until the blue color almost disappears, indicating that you are nearing the endpoint.

5. Complete the titration: At the point when the blue color is about to disappear, very carefully and slowly add the DCPIP solution dropwise, counting the number of drops, until the blue color is completely gone. This indicates the endpoint of the titration.

6. Repeat the titration: If the endpoint is not reached with the initial volume of DCPIP solution, repeat steps 3 to 5, adding the remaining volume in multiple portions until you reach the endpoint.

7. Calculate the concentration of vitamin C: Use the balanced equation between DCPIP and vitamin C to determine the stoichiometry of the reaction. From the volume of DCPIP solution required to reach the endpoint and the known concentration of the standard vitamin C solution, you can calculate the concentration of vitamin C in the sample using the following equation:

Concentration of vitamin C (mg/mL) = (Volume of DCPIP solution used x Concentration of standard vitamin C solution) / Volume of sample taken

In this equation, the volume of sample taken refers to the initial volume of the standard vitamin C solution (e.g., 10 mL).

Note: An aliquot is a measured portion of a sample, usually taken for analysis. In this particular problem, it is not necessary to use an aliquot since the titration is carried out directly in the 10-mL graduated cylinder.