quick question - esters

[nacho]

hi,
just had a sac today,
relatively simple, one question got me thinking (it was only a 1 marker)
It asked something along the lines of: "Would this ester (in relation to a previous question) be likely to react with water? Justify your response."

I put yes, in that it may undergo a hydrolysis reaction because of the presence of the water.
Many of my peers put "no" in that esters are immiscible, non-polar etc. From memory, the tail of the ester had more than 3 carbons present.
But my only thought is that, it is not asking if it will intermolecular bonds with or if it is soluble, it is asking if it will react with the water.

thanks,

[jane1234]

I would say yes, because they do hydrolyse which technically is a reaction with water. I think it needs an acid/base catalyst for it to occur though, so you might've needed to mention that a catalyst's presence was required.
I think you should be fine, as long as you backed your answer up with logical reasoning and/or examples.

[ariawuu]

"will intermolecular bonds with or if it is soluble, it is asking if it will react with the water" isn't it the same thing.. :S anyhow... i think it undergoes SLOW hydrolysis, but yes.. they should react with water and turn back into alcohol and carboxylic acid. It's a good question though.. pretty ambiguous to say. im not the best at chem though

[jane1234]

"will intermolecular bonds with or if it is soluble, it is asking if it will react with the water" isn't it the same thing.. :S anyhow... i think it undergoes SLOW hydrolysis, but yes.. they should react with water and turn back into alcohol and carboxylic acid. It's a good question though.. pretty ambiguous to say. im not the best at chem though

Just a technicality - if it hydrolyses in the presence of a base it won't return to the original carboxylic acid (COOH) but a (COO-) instead as it loses a H+ ion. So be careful in describing the hydrolysis of esters because it all depends on which catalyst is used...

[ariawuu]

"will intermolecular bonds with or if it is soluble, it is asking if it will react with the water" isn't it the same thing.. :S anyhow... i think it undergoes SLOW hydrolysis, but yes.. they should react with water and turn back into alcohol and carboxylic acid. It's a good question though.. pretty ambiguous to say. im not the best at chem though

Just a technicality - if it hydrolyses in the presence of a base it won't return to the original carboxylic acid (COOH) but a (COO-) instead as it loses a H+ ion. So be careful in describing the hydrolysis of esters because it all depends on which catalyst is used...

Ahh thanks jane!! -GOOD POINT

[nacho]

"will intermolecular bonds with or if it is soluble, it is asking if it will react with the water" isn't it the same thing.. :S anyhow... i think it undergoes SLOW hydrolysis, but yes.. they should react with water and turn back into alcohol and carboxylic acid. It's a good question though.. pretty ambiguous to say. im not the best at chem though

Just a technicality - if it hydrolyses in the presence of a base it won't return to the original carboxylic acid (COOH) but a (COO-) instead as it loses a H+ ion. So be careful in describing the hydrolysis of esters because it all depends on which catalyst is used...

I didn't mention the catalyst part,
but unlike in a condensation reaction to create an ester, a catalyst isn't essential?
The H2SO4 in the condensation reaction between and alcohol and carboxylic acid also aborbs water (preventing a hydrolysis reaction from occurring, thereby preventing the reversal of the reaction...to some extent anyway)
So i could still argue, that we can wait 500 years and the reaction would have taken place?

[jane1234]

"will intermolecular bonds with or if it is soluble, it is asking if it will react with the water" isn't it the same thing.. :S anyhow... i think it undergoes SLOW hydrolysis, but yes.. they should react with water and turn back into alcohol and carboxylic acid. It's a good question though.. pretty ambiguous to say. im not the best at chem though

Just a technicality - if it hydrolyses in the presence of a base it won't return to the original carboxylic acid (COOH) but a (COO-) instead as it loses a H+ ion. So be careful in describing the hydrolysis of esters because it all depends on which catalyst is used...

I didn't mention the catalyst part,
but unlike in a condensation reaction to create an ester, a catalyst isn't essential?
The H2SO4 in the condensation reaction between and alcohol and carboxylic acid also aborbs water (preventing a hydrolysis reaction from occurring, thereby preventing the reversal of the reaction...to some extent anyway)
So i could still argue, that we can wait 500 years and the reaction would have taken place?

I don't know. It might be an acceptable answer, but the reaction would never be used in real life. And the catalyst is just as "essential" in the hydrolysis as the condensation.
However, the question did just ask for the reactivity of the ester with water, so you might get away with not mentioning the catalyst... you could just ask your teacher.