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50:50 ethyl acetate and petroleum ether gives an rf value of about 0.6.You are supposed to dissolve the compound in any volatile solvent like methylene chloride or acetone.
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Arrange the following compounds in order of increasing Rf values in TLC Anthracene benzil tryphenylmethanol?
The order of increasing RF values in TLC is Benzil, methanol anthracene and tryphenyl.
What is rf value and how is determine?
the mobility of any component in a particular solvent is referred to as its RF value. Mathematically, RF value = distance travelled by solute/ distance travelled by the solvent
Why is that the centre of the spot is considered when calculating Rf values for TLC?
outside are jus impurities
If two samples have identical Rf values does this mean they are identical molecules?
Rf is a value that is usually seen in chromatography (such as thin-layer chromatography, or TLC). It is a measure of how far the compound has traveled along the stationary phase. This distance is affected by the compounds affinity to the stationary phase (the TLC plate) and its affinity to the mobile phase (the solvent). Generally this directly relates to the polarity of the compound, but other factors may influence this.Since similar compounds (in structure) also have similar dipole moments (polarity), similar compounds will typically have similar Rf values. However, there are exceptions and compounds that have different functional groups can end up having similar polarities and thus similar Rf values. TLC is usually used as an initial measure of identification. If the Rf of the reference matches the Rf of the unknown, it is likely the compounds are the same, but further investigation with other analytical techniques is necessary to confirm this.
Would RF values of amino acid you use in paper chromatography be the same if you use another solvent system?
Rf value is the ratio of distanced covered by solute by distanced covered by solvent.
Arrange the following compounds in order of increasing Rf values in TLC Anthracene benzil tryphenylmethanol?
The order of increasing RF values in TLC is Benzil, methanol anthracene and tryphenyl.
What are the TLC Rf values influencing factors?
Response Details:1) factor that affects the Rf value of TLC is the polarity of the solvent. If the solvent is too polar all of the compounds can run right up the plate resulting in poor separation.2) The RF value is used to established the identity of the spots of TLC plate.3) The RF value is ratio of the distance the solvent travels to the distance compound travels.4) The factors can affect RF values. The absorbent uniformity on the thin layer plate, same concentration(spotting is too weak or strong), room temperature during the mobile phase and development distance of the solvent during the mobile phase can all affect the results.5) Multiple solvent system are necessory when utilizing TLC for identification purposes.Response Details:1) factor that affects the Rf value of TLC is the polarity of the solvent. If the solvent is too polar all of the compounds can run right up the plate resulting in poor separation.2) The RF value is used to established the identity of the spots of TLC plate.3) The RF value is ratio of the distance the solvent travels to the distance compound travels.4) The factors can affect RF values. The absorbent uniformity on the thin layer plate, same concentration(spotting is too weak or strong), room temperature during the mobile phase and development distance of the solvent during the mobile phase can all affect the results.5) Multiple solvent system are necessory when utilizing TLC for identification purposes.
Will acetaminophen or ibuprofen have a higher Rf if you carry out a TLC separation of on a silica gel using a non-polar developing solvent?
Acetaminophen will have Rf value of about 0.4 and ibuprofen will have Rf value of about 0.6 if the non polar solvent used is ethanol.
A compound has a very high Rf value in a polar solvent what can you say about its molecular structure?
Rf Value - It tells you the affinity that the compound has to the solvent...High Rf = little or no polar groups and low Rf = more polar groups. Question: In TLC (thin-layer chromatography) when the compound has a high Rf the solvent is: a. less polar b. Is more polar Answer: a. less polar
Why is it necessary to run TLC in a closed container and to have the interior vapor saturated wit the solvent?
It is necessary to run TLC ina closed container and have the interior saturated with the solvent vapour to ensure maximum resolution between components and to prevent solvent evapourating off. If the solvent evapourate off, the Rf value would be lower than the expected value.
What is the RF value for paracetamol?
That depends on many factors including the elution solvent used, the type of TLC plate used, etc.. When using .5% of acetic acid in ethyl acetate as your elution solvent and on a plastic backed plate, the Rf-value should be around 79.82%
What is the maximum and RF value can be?
1, if it completely solube in the solvent, it will travel with it, right to the solvent front.
What is rf value and how is determine?
the mobility of any component in a particular solvent is referred to as its RF value. Mathematically, RF value = distance travelled by solute/ distance travelled by the solvent
What does an Rf value indicate?
Rf value indicates the relationship of the distance moved by a pigment to the distance moved by a solvent.The Rf can be calculated by the following equation. Rf=distance pigment migrated/distance solvent front migrated.
What is the Significance of Rf value?
· Used in identification pusposes · Use to determine the affinity of the solute to the solvent - Greater Rf , greater affinity of solute to the solvent
Why are Rf values always less than 1?
Rf values are distance of substance from origin divided by distance of solvent front from origin. As the substance travels with the solvent, the solvent will always have a greater or equal value to the distance travelled by substance. This means the highest value of Rf is 1.
What do the Rf values indicate about the relative solubility of the pigment in the the solvent?
The Rf values do not indicate the solubility of a substance. The Rf value or retardation factor is the ratio of the distance traveled by the center of a pot to the distance traveled by the solvent front in chromatography.
