In: Chemistry
In each pair, pick the molecule which would have the higher Rf value. Explain your answers.
a. Phenyl chloride or phenol
b. N,N-dimethylformamide or 1,3-butadiene
c. Acetonitrile or benzene
d. Decanol or propanol
a. Phenyl Chloride will have a higher Rf value as compared to phenol. Phenol is a polar protic compound. So, it will bind with a greater force to the static phase. It is also capable of forming hydrogen bonding with the silica or alumina surface. Therefore, phenol will have a lower Rf value.
b. N. N-dimethylformamide is a polar compound as compared to 1,3-butadiene. Therefore N, N-dimethylformamide will stick stronger to the static phase during chromatographic separation. So, N. N-dimethylformamide will have a lower Rf value.
c. Acetonitrile is a polar compound as compared to Benzene. The symmetric nature of Benzene ring makes it considerably less polar as compared to Acetonitrile. Therefore Acetonitrile will stick stronger to the static phase during chromatographic separation. So, Acetonitrile will have a lower Rf value.
d. Decanol and Propanol both the compounds have the same functional group. As the hydrophobic chain in Decanol is much more longer as compared to that of propanol Decanol is less polar as compared to Propanol. So, Propanol will have a lower Rf value.