Calculating Rf value in paper chromatography

Steps:

• Measure the distance from the baseline to the solvent front: 20 units.
• Measure the distance from the baseline to the center of spot M: approximately 6.6 units.
• Apply the Rf formula: Rf = (distance traveled by spot) / (distance traveled by solvent front).
• Compute Rf = 6.6 / 20 = 0.33.

Why C is correct:

• Rf is defined as the ratio of the spot's distance to the solvent front's distance, yielding exactly 0.33 for spot M.

Why the others are wrong:

• A: 0.22 would require spot M at 4.4 units, but it's higher.
• B: 0.25 would require spot M at 5 units, but it's farther.
• D: 0.43 would require spot M at 8.6 units, but it's lower.

Final answer: C