Question

For each of the following pairs of molecules, choose the molecules likely to have the higher Rf value and explain your answer. Be sure to include the relevant intermolecular forces in your discussion.

a) phenol or 4-nitrophenol

b) N,N-dimethylformamide or 1,4-cyclohexadiene

c) acetonitrile or benzene

d) decanol or propanol

Answer 1

For a compound to be eluted more , that is higher Rf, the compoud should be less polar compared to the other.

thus more polar of the pair has lower Rf and less polar has higher Rf values in the same eluant /mixture

a) phenol is less acidic than 4-nitrophenol. So phenol has higher Rf

b) 1,4 -cyclohexadiene is less polar and has higher Rf valu ethan N,N-dimethylformamide.

c)benzene is less polar and higher Rfthan acetonitrile.

d) propanol is more polar than decanol and decanol has higher Rf value.