Retardation (retention) factor (R_f) of four components A, B, C and D in thin layer chromatography (TLC) were found out be 0.9, 0.3, 0.6 and 0.5 respectively. The correct increasing order of their degree of adsorption on the glass plate is

TLC is an example of ascending chromatography. Most adsorbed component will have least value of R_f.

${\mathrm{R}}_{\mathrm{f}}=\frac{\text{Distance travelled by component}}{\text{Distance travelled by solvent}}$

$\therefore$The component which is least adsorbed will have higher value of R_f.

R_f ….             A > C > D > B

Degree of adsorption : A < C < D < B