[thetada]

Look again at the first question and see if you can find any information that conflicts with your suggestion

[Sush_eera]

Look again at the first question and see if you can find any information that conflicts with your suggestion

Is there something wrong in what I said? Cus i couldnt figure out where i went wrong

[thetada]

You need to go backwards. You use the information from step 3 to figure out how much excess sulfuric acid reacted with the sodium hydroxide. From that you work out how much ethanoic acid reacted with the sulfuric acid in step 2 and from that you work out what proportion of the 10g of powder in step 1 consisted of sodium ethanoate. My impression is that you were thinking that all of the 10g in step 1 was sodium ethanoate.

[Sush_eera]

You need to go backwards. You use the information from step 3 to figure out how much excess sulfuric acid reacted with the sodium hydroxide. From that you work out how much ethanoic acid reacted with the sulfuric acid in step 2 and from that you work out what proportion of the 10g of powder in step 1 consisted of sodium ethanoate. My impression is that you were thinking that all of the 10g in step 1 was sodium ethanoate.

But why would H₂SO₄ react with NaOH.. i though it would only react with ethanoic acid from the reaction i used before

[Borek]

But why would H₂SO₄ react with NaOH.

Because that's the way these substances behave. Whenever you have strong acid and strong base you can be sure they will react. When there is a mixture strongest bases/acids react first.

[thetada]

But why would H₂SO₄ react with NaOH.

Because that's the way these substances behave. Whenever you have strong acid and strong base you can be sure they will react. When there is a mixture strongest bases/acids react first.

This is interesting. I was starting to think that my suggestions were flawed. We use the sulfuric acid to turn the sodium ethanoate into ethanoic acid, then we titrate whatever sulfuric acid is left over against the sodium hydroxide, which tells us how much sulfuric acid was left over and hence how much sodium ethanoate there was to start with. But suddenly I realised that if the whole reaction mixture is titrated against the sodium hydroxide, it will neutralise first the sulfuric acid and then the ethanoic acid. In effect, it will neutralise all the protons that were originally associated with the sulfuric acid. This feels like a problem.

[Borek]

IMHO this is a poor question - ethanoic acid is way too strong for this kind of approach (at least in water solution). While sometimes choice of an indicator makes it possible to separately titrate two acids in one sample, I am not convinced it is possible here.

[thetada]

I'm glad you agree. Presumably whoever wrote it is expecting us to pretend that the ethanoic acid does not interfere with the titration of excess sulfuric acid against sodium hydroxide, as unrealistic as that might be.