Arrange the following compounds in order of increasing ease of elution from an activated alumina column:
a. Cyclohexane
b. Butyl acetate
c. Benzoic acid
d. M-xylene
e. Decyl alcohol
a,c,b,d,e
To arrange the given compounds in order of increasing ease of elution from an activated alumina column, we need to consider the polarity and the molecular weight of each compound.
1. Cyclohexane: Cyclohexane is nonpolar and has a low molecular weight. Nonpolar compounds do not interact strongly with the polar alumina and are usually eluted first. Cyclohexane will be eluted the fastest.
2. Butyl acetate: Butyl acetate is a polar compound due to the presence of the acetate group. It has a higher molecular weight than cyclohexane. Polar compounds interact more with the polar alumina, resulting in slower elution than nonpolar compounds. Butyl acetate is expected to elute after cyclohexane.
3. Benzoic acid: Benzoic acid is highly polar due to the presence of a carboxylic acid group. It has a higher molecular weight than both cyclohexane and butyl acetate. Being more polar, benzoic acid will interact more with the alumina, resulting in slower elution compared to the previous compounds.
4. M-xylene: M-xylene is a nonpolar compound similar to cyclohexane. However, it has a higher molecular weight. Like cyclohexane, it will elute faster than polar compounds due to weak interactions with the alumina but slower than cyclohexane due to its higher molecular weight.
5. Decyl alcohol: Decyl alcohol is a long-chain alcohol and polar due to the hydroxyl group. It is the most polar compound among the given options. Polar compounds with higher molecular weight have stronger interactions with alumina, resulting in slower elution. Decyl alcohol is expected to elute last.
Therefore, the order of increasing ease of elution from an activated alumina column is:
a. Cyclohexane
b. Butyl acetate
c. M-xylene
d. Benzoic acid
e. Decyl alcohol