Rob Posted October 11, 2009 Share Posted October 11, 2009 OK, a titration question for you here: "In order to determine the aspirin content of a commercial aspirin tablet, a tablet weighing 0.400g was dissolved in aqueous ethanol and titrated with 0.100M NaOH solution: 16.7cm^3 of the NaOH was required to reach the end point. Under the conditions of the titration, only the Carboxylic acid group reacts with the NaOH". Obviously, the question goes on to ask about moles in the aspirin, and the % by mass of aspirin in the tablet, but what I need to know is what is the balanced equation for this reaction? NaOH + COOH -> ? Cheers, Thanks for your help. Link to comment Share on other sites More sharing options...
Fuzzwood Posted October 11, 2009 Share Posted October 11, 2009 COOH is an acid group. HCl + NaOH gives water and NaCl, H2SO4 + 2 NaOH gives 2 water + Na2SO4 COOH + NaOH --> water and ??? 1 Link to comment Share on other sites More sharing options...
Rob Posted October 12, 2009 Author Share Posted October 12, 2009 Well, I though NaCO3, but something in the balancing didn't seem to add up Link to comment Share on other sites More sharing options...
Melvin Posted October 12, 2009 Share Posted October 12, 2009 It would probably just react to give the salt of sodium and aspirin (sodium acetylsalicylate?) NaOH + CH3COOC6H4COOH --> CH3COOC6H4COONa + H2O I would think the NaOH would break apart the ester though (to sodium acetate and sodium salicylate) Link to comment Share on other sites More sharing options...
Fuzzwood Posted October 12, 2009 Share Posted October 12, 2009 Yeah, because aspirin is of course a lot more than just COOH, like Melvin stated. Link to comment Share on other sites More sharing options...
hermanntrude Posted October 12, 2009 Share Posted October 12, 2009 It would probably just react to give the salt of sodium and aspirin (sodium acetylsalicylate?) NaOH + CH3COOC6H4COOH --> CH3COOC6H4COONa + H2O I would think the NaOH would break apart the ester though (to sodium acetate and sodium salicylate) however, the question explicitly states that ONLY the COOH group reacts with the NaOH at the conditions of the titration. Link to comment Share on other sites More sharing options...
Rob Posted October 14, 2009 Author Share Posted October 14, 2009 Its OK guys, don't fret too much any more - NaOH + COOH -> COONa + H2O Link to comment Share on other sites More sharing options...
hermanntrude Posted October 14, 2009 Share Posted October 14, 2009 Its OK guys, don't fret too much any more - NaOH + COOH -> COONa + H2O well done. that's the reaction they're expecting you to work with Link to comment Share on other sites More sharing options...
Acs Posted April 17, 2019 Share Posted April 17, 2019 It states "only the COOH group reacts with the NaOH" because the Acetyl group also reacts with it naturally, which forms sodium acetate (as far as I'm concerned) besides the sodium salicylate, which makes the whole reaction a 1:2 ratio in regards to Aspirin : NaOH. But when only the COOH group reacts with it as the task says, you don't have to take the Na-Acetate part into consideration, the ratio of the reactants are 1:1 I suppose, resulting in: C8H7O2COOH + NaOH = C8H7O2COONa + H2O. Link to comment Share on other sites More sharing options...
peterwlocke Posted April 17, 2019 Share Posted April 17, 2019 (edited) NaHO3 plus H2O Edited April 17, 2019 by peterwlocke Link to comment Share on other sites More sharing options...
MigL Posted April 18, 2019 Share Posted April 18, 2019 I just take my aspirin straight, without the caustic. Less stomach ulcers that way. Link to comment Share on other sites More sharing options...
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