Lastly, Snape thinks we should try one more calculation.
What is the retention factor if the distance traveled by the solvent front is 2.0 cm, and the distance the ion is from the solvent front is 0.20 cm?

A) 0.50 B) 0.60 C) 0.70 D) 0.80 E) 0.90

E) 0.90

Explanation:

In TLC (Thin-Layer-Chromatography) retention factor RF is defined as the ratio between distance of the sample and the solvent front. RF is very important in chemistry to know the composition of any sample by comparison.

In the problem, as the sample has a distance of 0,20cm from the solvent front, the distance of the sample is:

2,0cm - 0,20 cm = 1,8 cm. Thus, RF is:

RF = 1,8cm / 2,0cm = 0,90

E) 0,90

I hope it helps!

c. 75.7

i think that is the right