esterification (1 Viewer)

[chunder]

when purifying your ester after refluxing you add water etc.....
However why do you add NaHCO3 on the final purification? What is the chemistry behind this?

In prac exams can you be penalised for not wearing your labcoat etc.....

In prac exams is it worth making up your results and blaming any discrepancies on experimental error? It seems like a mad prac exam technique. Obviously you give yourself a rough idea by working it out theoretically first before making up the results.

 

[BlackJack]

I'd say adding NaHCO3 serves to neutralise the solution, as the hydrogen carbonate ion is amphiprotic. I don't remember some of the details, but you had concentrated sulfuric acid in there right? It makes your ester and/or the separated aqueous solution sorta... dangerous... (esp. if you try to smell it while the sulfuric acid is still inside)

Hmm... if you do stuff your prac exam up, it's really up to you whether to make it up or not. However, your teacher may give you the marks if you explained what did go wrong, talk to them 'bout it. Experimental error should be explained clearly as to how did it affect and where did the difference go.

eg. heat loss to environment in heat of reactions, as beakers, naked flame, etc.

If you really need a labcoat in your lab, your school is too rich.

 

[Toodulu]

don't you do the pracs in class anyway? i can't be bothered to make up results, just copy it off somewhere if i missed the lesson and don't want to do it after school.

and i think the NaHCo3 absorb impurities... maybe.
can't remember.

 

[elizabethy]

Originally posted by chunder
when purifying your ester after refluxing you add water etc.....
However why do you add NaHCO3 on the final purification? What is the chemistry behind this?

In prac exams can you be penalised for not wearing your labcoat etc.....

In prac exams is it worth making up your results and blaming any discrepancies on experimental error? It seems like a mad prac exam technique. Obviously you give yourself a rough idea by working it out theoretically first before making up the results.

in order to obtain pure ester , it is necessary 2 remove the impurities such as alcohol, acid,etc..... thus bases such as NaHCO3 help to neutralise the acid and we can get a pure ester!!! by thw way water is added to remove the alcohol......