Question: What Would Happen If The Solvent Level Was Above That Of The Dye Spots On The Paper At The Start Of The Development?

Why must the spots be above the solvent level?

It is important to keep the dye spots above the solvent level because if the spot is not below the solvent level, the molecules will not dissolve into the solvent and, then, would not be able to separate D..

Why is it important to mark the solvent front immediately?

It’s important only if you want to determine retention/retardation factor absolutely for something you chromatographed. “Immediately” because it will soon vanish as the solvent evaporates. … Solvent front is the the furthest point reached by the solvent in chromatography.

Why can’t the solvent touch the pencil line?

If your start line is inside the solvent or equal to level of solvent it can cause error. The solvent gives extra energy to pull up the sample and the sample will also dissolve in the solvent. That’s why as precautionary measure start line should stay above the solvent in chromatography!

Which color was attracted to the mobile phase the most?

CaroteneBriefly explain the reasoning you used to identify this pigment. Out of all the pigments, Carotene was the most attracted to the mobile phase. Carotene was the most attracted because it was less charges or uncharged causing it to be more attracted to the mobile phase and be the furthest from the origin.

Why is it important to remove the chromatography paper?

Why is it important to remove the chromatography paper from the beaker before the solvent front reaches the top of paper? Because you wouldn’t be able to measure the rf value unless you can measure the start to front of the solvent on the chromatography paper.

What is the solvent front?

[′säl·vənt ‚frənt] (analytical chemistry) In paper chromatography, the wet moving edge of the solvent that progresses along the surface where the separation of the mixture is occurring.

What happens if the spots are made too large when preparing a TLC plate for development?

What happens if spots are made too large when preparing a TLC plate for development? Why must the spots be above the level of development solvent in chamber? They will dissolve in the development solvent if they were submerged.

What would happen if the solvent level is above the start line?

The solvent level has to be below the starting line of the TLC, otherwise the spots will dissolve away. … Non-polar solvents will force non-polar compounds to the top of the plate, because the compounds dissolve well and do not interact with the polar stationary phase.

How long should you run a TLC plate for?

Question: How Long Should You Run A TLC Plate For? Until The Solvent Front Is About Half Way Up. Until The Solvent Front Is At The Top Of The Plate. 2 Minutes.

Does a higher Rf value mean more polar?

In general, the adsorptivity of compounds increases with increased polarity (i.e. the more polar the compound then the stronger it binds to the adsorbent). … Non-polar compounds move up the plate most rapidly (higher Rf value), whereas polar substances travel up the TLC plate slowly or not at all (lower Rf value).

What would the result be if the spots are too concentrated in a TLC experiment?

Streaking: If the sample spot is too concentrated, the substance will travel up the stationary phase as a streak rather than a single separated spot. In other words, the solvent can not handle the concentrated sample and in result, moves as much of the substance as it can up the stationary phase.

What does the RF value tell you?

The Rf values indicate how soluble the particular pigment is in the solvent by how high the pigment moves on the paper. Two pigments with the same Rf value are likely to be identical molecules. Small Rf values tend to indicate larger, less soluble pigments while the highly soluble pigments have an Rf value near to one.

Why is it important the ink dots are not submerged in the solvent?

It is important that the solvent level is below the line with the spots on it. … As the solvent slowly travels up the paper, the different components of the ink mixtures travel at different rates and the mixtures are separated into different colored spots.

What happens if the solvent front reaches the top of the plate?

However, if the solvent reaches the top of the plate, the chemicals continue to move up. This means that if left long enough, the chemicals will all merge together at the top of the plate, eliminating any separation that you could have seen on the plate.

What has happened to the size of the starting material spots Why?

The size of the starting materials spots has decreased in size. This has happened as the material has moved up the TLC. How much time did it take to complete the reaction? It took about 34 mins for the reaction to complete.

What would happen if the student did not stop the development before the solvent reached the top of the paper?

What would happen if the student did not stop the development before the solvent reached the top of the paper? The solvent would wash away the dye.

Which solvent system gave the best results?

Which solvent system gave the best results? The 75% hexane and 25% ethyl acetate gave the best results.

Why do some pigments move farther than others?

The pigments are carried at different rates because they are not equally soluble. A pigment that is the most soluble will travel the greatest distance and a pigment that is less soluble will move a shorter distance.

Why are two solvents used in chromatography?

Ans 1) Acetone and ethanol are two solvents used in thin layer chromatography for plant pigments. … The solvents help to dissolve the plant pigments as soon as the solvent moves across the pigment. The pigments that are more soluble tend to move the paper upwards than the pigments that are more soluble.

Why is the starting line drawn in pencil?

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. The paper is left vertically in a solvent. … Substances have different Rf values in different solvents.

Why must the spot be above the level of the development solvent in the developing chamber?

If the level of the solvent system in the chamber is above the spot when the plate is inserted, the compound from the spot will dissolve in the solvent instead of migrating up the plate.