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Topic: solubility of aspirin  (Read 106592 times)

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Offline cuongt

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solubility of aspirin
« on: July 16, 2006, 06:02:17 PM »
why is aspirin insoluble in water? is it because it only has one OH bond(hydorgen bond) and also its structure is a large non polar component?
and when NaHCO3 is added why does it make aspirin soluble in water?( this i dont get  :D)

Offline Yggdrasil

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Re: solubility of aspirin
« Reply #1 on: July 16, 2006, 06:31:07 PM »
Yes, since most of aspirin is non-polar, it is insoluble in water.

For your second question, think about how sodium bicarbonate reacts with asprinin (hint: aspirin = acetylsalicylic acid) and how this changes the properties of aspirin to make it more soluble.

Offline cuongt

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Re: solubility of aspirin
« Reply #2 on: July 16, 2006, 08:07:04 PM »
TY TY TY ROFL  :P :D

Offline Albert

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Re: solubility of aspirin
« Reply #3 on: July 17, 2006, 02:58:06 AM »
For your second question, think about how sodium bicarbonate reacts with aspirin (hint: aspirin = acetylsalicylic acid) and how this changes the properties of aspirin to make it more soluble.

NaHCO3 reduces disaggregation time due to effervescence. The reaction between NaHCO3 and acetylsalicylic acid yields H2CO3 (hence, H2O + CO2). The bubbles act like an explosive.

Offline Yggdrasil

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Re: solubility of aspirin
« Reply #4 on: July 17, 2006, 03:24:55 AM »
However, powdered acetylsalicylic acid is still going to be largely insoluble in water.  The main purpose of the sodium bicarbonate is to deprotonate the carboxylic acid in acetylsalicylic acid to produce a sodium acetylsalicylate salt which is much more soluble in water (due to the presence of a charged carboxylate group).  The effervesence, as Albert noted, will help the sodium acetlysalicylate disolve faster.

Offline cuongt

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Re: solubility of aspirin
« Reply #5 on: July 17, 2006, 03:48:31 AM »
wow soo much depth thanx for explanation and help guys  ;)

Offline TheMantis

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Re: solubility of aspirin
« Reply #6 on: September 13, 2015, 04:02:16 PM »
Actually, Aspirin is partially soluble in water.  The reason why it is only partially soluble in water is because of its hydrophobic portion of the molecule.  Also, the hydrogen on the carboxylic acid functional group can hydrogen bond with the oxygen atom of the ester carbonyl group making it even further less soluble in water.

When you treat aspirin with sodium bicarbonate, it undergoes an acid base reaction to give you a sodium carboxylate, which is an ionic species of aspirin, thus making it water soluble.  Also, the intermolecular hydrogen bonding affect is now absent because the proton on the carboxylic acid is now gone.

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