Question

Results: Distance of the solvent front in mm: 55 mm Compound acetanilide acetylsalicylic acid acetaminophen ibuprofen phenacetin Solute distance R value colour of spot / observations Saturated purple colour 0.55 Elongated purple colour 22 mm 30 mm 6 mm 47 mm 12 mm 0.40 Saturated purple colour 0.85 Elongated purple colour Saturated purple colour 0.11 0.22 Unknown #-5 Compound compound 1 compound 2 contains the following compounds: Solute distance Rf value colour of spot / observations 0.22 Saturated purple colour 0.51 Elongated purple colour 12 mm 28 mm Questions: 1. What is the most polar compound of the group of analgesics? The least polar? (2 marks) 2. What would happen if you used ink to mark your TLC plate? (2 marks)

Answer 1

1.

Generally compounds having least RF value is highly polar compound, while high RF value is least polar ( most non polar)

Acetaminophen (RF value 0.11) is highly polar compound, while least polar compound is ibuprofen (RF value is 0.85).

2.

You can not use a pen on tlc plate, because the ink also traveled up the tlc plate along with the mobile phase, like u r chemical samples.

If you can spot with pencil on tlc plate the graphite on tlc plate will not move along with mobile phase.