Answer :
In chromatography, a mixture of substances is separated to identify its components. When Sam places a dot of purple ink on the filter paper, the chromatography process works to separate the different dyes that make up the ink.
Since purple ink is made by mixing red and blue dyes, when Sam performs the chromatography experiment, two separate spots should appear above the original purple ink spot on the paper: one red and one blue.
Here's how it works step-by-step:
Starting point: A dot of purple ink is placed near the bottom of the filter paper.
Solvent action: The paper is then immersed in a suitable solvent (often water or alcohol), but only the part below the ink dot.
Capillary action: The solvent rises up the paper due to capillary action, passing through the spot of ink.
Separation of dyes: As the solvent moves through the ink, it dissolves different dyes at different rates based on their solubility and affinity for the paper, separating them.
Result on paper: Once the process is complete, you will see two distinct dots on the paper above the original purple ink spot, indicating the red and blue dyes.
Therefore, the correct answer is 2 dots of ink will appear above the sample of purple ink.
In the chromatography practical described, Sam places a dot of purple ink, which is a mixture of red and blue dyes, on filter paper. Chromatography is a technique used to separate the different components of a mixture based on their movement at different rates.
When the solvent moves up the filter paper, it carries different dyes with it. Each dye travels at a different speed depending on its properties, such as its affinity to the solvent and the paper. Since purple is a combination of red and blue dyes:
The red dye will appear as one dot.
The blue dye will appear as another dot.
Therefore, above the sample of the initial purple ink, you will observe two separate dots of ink on the paper, corresponding to the red and blue components.
So, the correct answer is 2 dots of ink.
