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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: macca69831 on May 15, 2010, 05:38:37 pm

Title: Organic Pathways, a few quick questions
Post by: macca69831 on May 15, 2010, 05:38:37 pm
1. What chemical test could be used to distinguish ethanoic acid and propan-1-ol?

2. What does the reaction of butanoic acid with Na2CO3 (aq) suggest about butan-1-ol?

3. Why does propan-1-ol have a higher boiling point than ethanol?
Title: Re: Organic Pathways, a few quick questions
Post by: Akirus on May 15, 2010, 07:13:11 pm
1. Infrared/NMR

3. Larger molecules have more dispersion forces -> requires more energy to break intermolecular bonds, I believe.

No idea about the second one, to be honest. I don't see the correlation.
Title: Re: Organic Pathways, a few quick questions
Post by: superflya on May 15, 2010, 07:26:16 pm
the reaction would produce sodium butanoate + CO2 + water i think. butan-1-ol?
Title: Re: Organic Pathways, a few quick questions
Post by: kakar0t on May 15, 2010, 07:52:23 pm
2. acid/base reaction
Title: Re: Organic Pathways, a few quick questions
Post by: superflya on May 15, 2010, 08:02:01 pm
Quote from: kakar0t on May 15, 2010, 07:52:23 pm
2. acid/base reaction

yea... :P
Title: Re: Organic Pathways, a few quick questions
Post by: Akirus on May 15, 2010, 08:18:23 pm
When I said I had no clue, I meant that I don't see what the acid/base reaction to form CH3(CH2)2COONa + CO2 + H2O has to do with butan-1-ol.
Title: Re: Organic Pathways, a few quick questions
Post by: Nomvalt on May 15, 2010, 08:24:11 pm
How did you guys know that Na2CO3 reacts with butanoic acid to form an ester? I mean from the formula of Na2CO3, it looks like there are no -OH groups and hence it shouldn't be able react with butanoic acid to form sodium butanoate. Please excuse my ignorance.
Title: Re: Organic Pathways, a few quick questions
Post by: Akirus on May 15, 2010, 08:29:30 pm
Quote from: Nomvalt on May 15, 2010, 08:24:11 pm
How did you guys know that Na2CO3 reacts with butanoic acid to form an ester? I mean from the formula of Na2CO3, it looks like there are no -OH groups and hence it shouldn't be able react with butanoic acid to form sodium butanoate. Please excuse my ignorance.

It's not a condensation reaction, just a normal acid/base reaction where an acid (butanoic acid) reacts with a carbonate (sodium carbonate, in this case) to form water and carbon dioxide. I don't think it's an ester (although I could be wrong, hazarding a guess here).
Title: Re: Organic Pathways, a few quick questions
Post by: Nomvalt on May 15, 2010, 08:41:40 pm
Right, yeah I just assumed it was an ester. Makes sense.
Title: Re: Organic Pathways, a few quick questions
Post by: Mao on May 16, 2010, 02:21:12 am
I'm going to be technical here and say for question 1, a chemical test (not an instrumental analysis) could be addition of  sodium carbonate. Ethanoic acid would create bubbles (as CO2 gas released from the carbonate group on neutralization), propanol won't do anything. In fact, most pH indicator will work to distinguish between an alkanol and carboxylic acid.

As for question 2, that's either a very poorly worded question, or it is absolutely pointless as everyone has said.
Title: Re: Organic Pathways, a few quick questions
Post by: Martoman on May 16, 2010, 05:50:09 pm
Yeah I was sitting here for a full 2 mins thinking hard about the second one thinking its rubbish.