a)
Interpretation:Reason for streaks of
Concept introduction:TLC or thin layer chromatography is technique that is used to separate various components of mixture with help of stationary phase and mobile phase. It makes use of silica gel, cellulose or aluminum oxide. This procedure is widely used because of its simplicity, low cost efficiency, and high sensitivity.
b)
Interpretation:Purpose of addition of acetic acid to reduce streaking should be explained.
Concept introduction:TLC or thin layer chromatography is technique that is used to separate various components of mixture with help of stationary phase and mobile phase. It makes use of silica gel, cellulose or aluminum oxide. This procedure is widely used because of its simplicity, low cost efficiency, and high sensitivity.
c)
Interpretation:Substance that can be added to reduce streaks produced by
Concept introduction:TLC or thin layer chromatography is technique that is used to separate various components of mixture with help of stationary phase and mobile phase. It makes use of silica gel, cellulose or aluminum oxide. This procedure is widely used because of its simplicity, low cost efficiency and high sensitivity.
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EBK EXPERIMENTAL ORGANIC CHEMISTRY: A M
- 1. How does chromatography separate the components of leave samples? 2. Can you use chromatography to purify a mixture? why? 3. What is Rf value and its significance in chromatography?arrow_forward25. In the paper chromatography experiment on food dyes, salt water was used as the A. mobile phase B. stationary phase C. eluent D. solute E. sample spotsarrow_forwardFlavonols are a type of flavonoids, in a silica gel stationary phase chromatography, with what kind of intermolecular force do the functional groups of the molecule interact with the silane groups? a. hydrogen bond b. van der Walls force ionic bond C. d. ion-dipole Which of the following compounds would elute faster on a reverse phase chromatographic column? a. beta carotene b. limonene c. quercetin d. Tocopherolarrow_forward
- 7. In gas chromatography, increasing the column length leads to analytes, assuming all other parameters are kept constant. a. no effect on b. an increase in C. a decrease in 8. Suppose you are extracting an organic compound from an aqueous solution using retention time for dichloromethane. a. top layer b. bottom layer Once you mix the two layers together, which layer is the organic extract? 6001 9. Which way is best to remove an acidic impurity from an organic liquid that is immiscible with water? a. simple distillation b. wash with aqueous base c. wash with aqueous acid d. recrystallization it in diegolved in a volatilearrow_forward19. What is thin layer chromatography (TLC) LEAST useful for from the list below? A) To determine if crystallization or distillation may be more effective for a separation B) To determine the number of components in a mixture C) To determine the appropriate solvent for column- chromatographic separation D) To monitor the progress of an organic synthesis reaction 14. The solubility of salicylic acid in water is 7.8g/100ml at 100°C and 0.25g/100ml at 25°. Estimate how much water is needed to recrystallize a 19g sample of salicylic acid? A) 150ml B) 250ml C) 300ml D) 400mlarrow_forwardQUESTION 15 To improve the accuracy of our linear fit between absorbance and concentration, a. add an extra data point to your linear regression where you make the assumption that pure water has an absorbance of zero. b. make sure that you choose a "Linear Regression" curve fit. c. ensure that there are no air bubbles in the cuvette. O d. use the data points only at the lower end of the concentration range because Beer's Law is not applicable for higher concentrations. QUESTION 16 What laboratory equipment do you need to prepare a 0.250 M stock solution of NaCI? O a. buret, graduated cylinder, analytical balance b. beaker, volumetric flask O. volumetric pipet, analytical balance d. analytical balance, volumetric flaskarrow_forward
- CHROMATOGRAPHY HW 1. What does adsorb mean? 2. What is chromatography used for? 3. Why must a pencil rather than a pen be used to mark the TLC plate?arrow_forward19. What type of sample analysis usually operates on the 10-4 g scale of sample size? A. macro analysis C. micro analysis B. semi-micro D. ultra-micro analysis analysis 20. Under what classification does a constituent group when its concentration is between 100 ppm and 1ppb? A. Major constituents B. Interferences C. Minor D. Trace constituents constituentarrow_forwardPART1: Put True (T) or False (F) for the following sentences: 1. chromatography" derived from two Greek words "Chroma" meaning color and "graphein" meaning to write. The stationary phase may be a solid, or a liquid supported on a solid or gel. 3. The mobile phase may be 2. Solid. 4. Silica gel is the most common stationary phase in adsorption chromatography. 5. Liquid Chromatography abbreviated as (GC ). 6. In Thin Layer Chromatography, the mobile phase is gas. 7. a = KB/KA, where Kg is the distribution constant. 8. k'B and k'A are the retention factors. 9. Rf, is the distance traveled by the compound ONLY. 10. Chromatography is a physical method of separation.arrow_forward
- High performance liquid chromatography (HPLC) can be used to : a. identify the various pigments from a leaf extract. b. separate types of organic pesticides. c. determine the mercury content of a fish sample d. all of the above are correctarrow_forwardIn column chromatography, dyes with higher polarities tend to attach to which of the forbwing? A. THF-Acetone B. Silica C. Acetone D. Tetrahydrofuranarrow_forwardCHROMATOGRAPHY HW 1. What does adsorb mean? 2. What is chromatography used for? 3. Why must a pencil rather than a pen be used to mark the TLC plate? 4.If you make an error recording data, how would you correct it? Is it ok to erase it or white it out? 5.Using the data on the last slide, calculate the Rf value for each spot.arrow_forward
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