A spot (corresponding to a certain compound) has an R_f value of 0.30 when it wa

Question

A spot (corresponding to a certain compound) has an R_f value of 0.30 when it was initially spotted on a TLC plate at about 1.5 cm from the bottom edge of the plate. The TLC was inserted in a development chamber containing a 40 % acetone/60 % hexane solvent system and was removed alter the solvent front had reached about 0.50 cm from the top edge of the plate. The distance traveled by this spot was 3.6 cm up the plate. By showing all the calculation steps including the mathematical formula determine the following The distance (in cm) traveled up the plate by the solvent front. What is the overall length (in cm) of the TLC plate? Witt this spot more likely correspond to u nonpolar or a polar compound? Would the K, value of this compound increase or decrease if the TLC plate was developed in a 50 % acetone/50 hexane solvent system?

Explanation / Answer

Question a

The Distance of the TLC from bottom of the Edge and Spot = 1.5 cm
The Distance of the TLC from top of the Edge and solvent front = 0.5 cm
The distance travelled by the spot = 3.6 cm

Rf Value of the spot = 0.3

Hence The distance travelled by the solvent front = 100 x 3.6 /30 = 11.9998 ~ 12 cm

Question b

Over all length = distance travelled by the solvent front + The Distance of the TLC from bottom of the Edge and Spot +The Distance of the TLC from top of the Edge and solvent front

Over all length = 12 + 1.5 + 0.5 = 14 cm

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.