Table of Contents
- 1 Why is pencil used to draw the line in chromatography?
- 2 Why should the line at the bottom be drawn in pencil not pen?
- 3 Why do you use a pencil rather than a pen to mark the spotting line on a TLC plate?
- 4 Why is it important to not let the solvent run off the top of the plate?
- 5 Why is a pencil line drawn in chromatography?
- 6 Why is the starting line drawn above the solvent?
Why is pencil used to draw the line in chromatography?
In paper chromatography, a starting line in drawn on the paper in pencil (pencil so that it does not dissolve in the solvent and affect the results). Small spots of each sample are placed on the starting line. If a substance is more strongly attracted to the paper than the solvent then it will move a short distance.
Why should the line at the bottom be drawn in pencil not pen?
Answer and Explanation: In paper chromatography, the starting line must be drawn with the help of pencil because the pencil lead does not dissolve in solvent, thus it will not affect the separation. The spots of the compounds are separated correctly.
Why must a pencil be used to mark the origin line on the TLC plate more than 1 answer can be correct?
Why must a pencil be used to mark the origin line on the TLC plate? (More than 1 answer can be correct.) Graphite from the pencil lead is nonpolar & won’t move up the plate. Graphite is repelled by the TLC plate. -The ink from a pen is composed of organic compounds that will dissolve in the eluent.
Why must you use pencil and not pen when marking a TLC plate before it is developed?
Do not use excessive forces when writing on a TLC plate as this will remove the stationary phase. It is important to use a pencil rather than a pen because inks commonly travel up the plate with the solvent.
Why do you use a pencil rather than a pen to mark the spotting line on a TLC plate?
Developing a TLC plate requires a developing chamber or vessel. Do not use excessive forces when writing on a TLC plate as this will remove the stationary phase. It is important to use a pencil rather than a pen because inks commonly travel up the plate with the solvent.
Why is it important to not let the solvent run off the top of the plate?
Do not allow the solvent front to reach the top of the plate. That may cause erroneous Rf values and may cause spots that are close together to run into each other. Low polarity solvents will cause the spots to move more slowly.
Why must you use pencil to mark on the TLC plate?
Why do you use a pencil and not a pen to mark TLC plates? Answer: The pen ink becomes mobile on the plate and travels up the TLC plate with TLC solvent. But the solid particles of graphite in the pencil won’t get dissolved and hence can be used to mark TLC plates.
Why is the starting line drawn with a pencil?
Answer and Explanation: In paper chromatography, the starting line must be drawn with the help of pencil because the pencil lead does not dissolve in solvent, thus it will not affect the separation. The spots of the compounds are separated correctly. Why must the solvent level be below the Coloured spots in chromatography?
Why is a pencil line drawn in chromatography?
Separating dissolved solids – chromatography It works because some of the coloured substances dissolve in the solvent used better than others, so they travel further up the paper. A pencil line is drawn, and spots of ink or plant dye are placed on it.
Why is the starting line drawn above the solvent?
There is a container of solvent, such as water or ethanol. Also, why is the starting line drawn above the solvent? In thin layer or paper chromatography the origin should be above the solvent because it could otherwise wash the sample spot into the solvent trough.
Why is ink never used for drawing the baseline?
In preparing the chromatography paper, a baseline is drawn in pencil for the positioning the spots. Why is ink never used for drawing the baseline? The ink in the pen may also move with the solvent. This will create a mixed spot with the ink that is being tested.