On a thin layer chromatographic plate, an organic compound moved by...

Given, an organic compound moved by $3 . 5cm$

Solvent moved by $5cm$

The R_f (retardation factor) value is the ratio of the solute’s distance travelled to the solvent’s distance travelled.

Retardation factor $=$$\begin{array}{ll}Distancetravelledby \\ sample / organiccompound\end{array}$$Distancetravelledbysolvent$

By putting the values in the above formula,

${R}_{f} = \dfrac{3 . 5}{5} = 7 \times {10}^{- 1}$