a) Glycine is transparent in color it cannot identified on TLC plate due to its colour
b) Amino acids can be detected by spraying the TLC plate with Ninhydrin solution
c) The retardation factor is the ratio of the distance travelled by the solute to that of the solvent from the base line
d) Sodium chloride is commonly used as table salt it never has property of an adsorbent

The three most often utilised adsorbents in TLC are cellulose, silica gel, and aluminium oxide.