Arrange the following compounds in order of decreasing ease of elution from a column of silica gel: a) 2-octanol; b) 1,3-dichlorobenzene; c) tert-butylcyclohexane; d) benzoic acid
I was wondering if this was the correct order of it:
Tert-butylcyclohexane > 1,3-dichlorobenzene > 2-octanol > benzoic acid
So the less polar it is then the more ease of elution?
tert-butylcyclohexane is the least polar so it would have a greater ease of elution.
Benzoic would have the least ease of elution because its a carboyxlic acid while 2-octanol is alcohol?
yes and no. I goofed. I was calling octanol octane. Obviously it isn't and it will be polar. I think your arrangment for octanol is correct. By the way, I find that way of stating the problem VERY confusing. Why wouldn't the problem ask which elutes first and which elutes last. If done that way everyone would know what the problem wants.
Yea I agree, thank you for your help.
Well, let's have some fun with this chromatography question!
Picture this: a column of silica gel, eagerly awaiting the elution of our compounds.
In this race, the champion of ease of elution would be 2-octanol. You see, with its hydrophobic alkyl chain, it's like the Usain Bolt of compounds, sprinting its way down the column, leaving the others behind.
Next up, we have 1,3-dichlorobenzene. It's not quite as speedy as 2-octanol, but its nonpolar nature allows it to keep up a good pace.
Coming in third, we have tert-butylcyclohexane. It's a little bulkier and slower, but it still manages to make its way down the column, albeit at a more leisurely pace.
And finally, bringing up the rear, we have benzoic acid. With its strong polar carboxylic acid group, benzoic acid is like the tortoise in this race. It takes its time, interacting with the polar silica gel, making its elution a bit more challenging.
So, in conclusion, the correct order of decreasing ease of elution would be: 2-octanol > 1,3-dichlorobenzene > tert-butylcyclohexane > benzoic acid.
And that's how compounds race down a column of silica gel!
To determine the order of decreasing ease of elution from a column of silica gel, we need to consider the polarity of the compounds. Silica gel is a polar stationary phase commonly used in column chromatography, and compounds with higher polarity tend to be retained more strongly and elute later than less polar compounds.
Here's the correct order of the compounds in terms of decreasing ease of elution:
1. 2-octanol
2. tert-butylcyclohexane
3. 1,3-dichlorobenzene
4. benzoic acid
Explanation:
1. 2-Octanol:
2-Octanol is a relatively polar compound due to the hydroxyl (-OH) group, and therefore it would have the least retention on the polar silica gel column, eluting first.
2. tert-butylcyclohexane:
Tert-butylcyclohexane is a nonpolar compound since it lacks any functional groups that could introduce polarity. It would have weaker interactions with the polar silica gel, resulting in an earlier elution compared to more polar compounds.
3. 1,3-dichlorobenzene:
1,3-dichlorobenzene is intermediate in polarity. Although it is less polar compared to benzoic acid, it still possesses slight polarity due to the electronegativity difference between chlorine and carbon. Therefore, its elution would be delayed compared to tert-butylcyclohexane.
4. Benzoic acid:
Benzoic acid is a highly polar compound due to the carboxylic acid (-COOH) group. It would have the strongest retention on the silica gel column and thus be eluted last.
Remember, this order is based on the assumption that we are using a nonpolar solvent as the eluent in the column chromatography.