Question

Using TLC, unknown A was determined to have an Rf value of 0.87, unknown B was 0.64 and unknown C was 0.24. Which unknown is the most polar? How do you know?

Answer 1

In TLC, silica gel is polar so the polar compounds adhere to the silica gel runs slowly on the tlc plate giving a low rf value where as non polar compounds do not stick to the silica gel runs very fast on the tlc plate giving rise to high rf value.so the conclusion is polar compounds will have low rf value and non polar compounds will have high rf value.

unknown c is the most polar compound since it is having least rf value

unknown A is the most non polar and unknown B is moderately polar