so we did this lab on chromatography, and in the beaker was 10 mL of HCI and 35 mL of acetone.

IF the distilled water used to prepare the HCI solution in this experiment passed through iron pipes, then the HCI will be contaminated with FeCl3. Examine your chromatography paper carefully. If this impurity is present, it will appear as a streak of color across the length of the paper, rather than as a spot. WHy? If it is not present, still explain why its presence as an impurity would result in a streak rather than a spot.

My paper does seem to have any streak, but still why would its presence as an impurity result in streaks rather than a spot?

The closest I can find to a reason for streaking is that the sample spot was overloaded. Here is the link and it's at the end of the page.

http://orgchem.colorado.edu/hndbksupport/TLC/TLC.html

It will appear as an orange/brown stain across the WIDTH of the paper because it moves with the solvent front up the paper.

It appears across the WIDTH of the paper because it is present in the mobile phase.
It tends to be more obvious than you might expect because of the white of the paper.

The presence of FeCl3 as an impurity in the hydrochloric acid (HCI) solution would result in streaks rather than spots on the chromatography paper due to its properties and behavior during the chromatography process.

Chromatography works based on the principles of separation and movement of different solutes in a solvent. When a solute is applied onto the chromatography paper and the solvent (in this case, acetone) moves up the paper, it carries the solutes along. These solutes will separate at different rates based on their affinity for the paper and the solvent being used.

FeCl3, when present as an impurity in HCI, forms a complex with water molecules (FeCl3 • xH2O). This complex has a higher affinity for the chromatography paper compared to the other components in the solution like HCI. As the solvent (acetone) moves up the paper, it carries all the solutes, including the FeCl3 complex. However, due to its higher affinity for the paper, it tends to remain in a specific region, resulting in a streak rather than a spot.

When FeCl3 is absent, the HCI solution does not contain this impurity. The other components of the solution, such as HCI, do not form complexes with water like FeCl3 does. As a result, all the solutes in the solution, including HCI, are carried uniformly by the solvent up the chromatography paper, resulting in spots rather than streaks.

Since you mentioned that your paper does not seem to have any streak, it suggests that the HCI solution used in your lab does not contain FeCl3 impurity. However, it is still important to examine the chromatography paper carefully to ensure the absence of any streaks.

In chromatography, a mixture of substances is separated into its individual components based on their different solubilities. The paper used in chromatography, known as the chromatography paper, acts as the stationary phase, while the mobile phase (in this case, the mixture of HCI and acetone) moves up the paper via capillary action.

When a spot of a substance is placed on the chromatography paper and the mobile phase moves up, the different components of the spot will separate based on their different affinities for the paper and the mobile phase. This separation creates distinct "spots" on the paper, representing the individual components of the mixture.

However, in the case of an impurity like FeCl3 in the HCI, the presence of FeCl3 would result in streaks rather than a spot on the chromatography paper. This is because FeCl3 is a soluble compound and when the mixture of HCI and acetone moves up the paper, the FeCl3 will dissolve into the mobile phase. As a result, the FeCl3 will spread out along the length of the paper, creating a streak instead of a concentrated spot.

Even if the chromatography paper in your experiment does not show any streak, the reason why the presence of FeCl3 as an impurity would result in streaks is because it is a soluble compound. Soluble compounds tend to dissolve into the mobile phase and distribute themselves more evenly throughout the paper, rather than remaining concentrated in a single spot.

It is important to examine the chromatography paper carefully because the presence or absence of streaks can provide valuable information about the purity of the HCI solution and whether it is contaminated with FeCl3.