Identifying unknown organic compounds

[Shaybay92]

Homework Statement

A chemist has three liquids (Ethanol, butanoic acid and 3-heptyne) labelled P,Q,R (in no specific order). When drops of bromine solution were added to samples of each liquid, P and Q decolorised the bromine, but R did not. When drops of sodium carbonate solution were added to fresh samples, R produced bubbles of colourless gas, but P and Q did not. When ap iece of sodium metal was added to fresh samples of the three liquids, P and R produced bubbles of gas, but Q did not.

Find P, Q, R and give equations for each of the reactions that occurred.

The Attempt at a Solution

P - Reacted with Bromine, Reacted with sodium to give gas
Q - Reacted with Bromine
R - Gave off bubbles with Na2CO3, Reacted with sodium to give gas

I'm not sure of the reaction with metallic sodium. What gas is given off when it is added to organic compounds? Also does bromine only react with the butanoic acid and heptyne because they have double/triple bonds??

 

[Borek]

I'm not sure of the reaction with metallic sodium. What gas is given off when it is added to organic compounds?

It can react with slighly acidic protons - similarly to the reaction with water.

Also does bromine only react with the butanoic acid and heptyne because they have double/triple bonds??

Yes for heptyne, no for butyric acid.

http://en.wikipedia.org/wiki/Bromine#Organic_chemistry

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[Blueshift5]

you would need more information to accurately identify the unknown compounds P, Q, and R. While the reactions described can give some clues about the properties of these compounds, they are not sufficient to determine their chemical structures. In order to accurately identify the compounds, you would need to perform further tests and analyses, such as infrared spectroscopy or mass spectrometry, to determine the functional groups and molecular structures present in each compound. Additionally, you may need to compare the results of these tests with known compounds in order to make a definitive identification. Without this additional information, it is difficult to give equations for the reactions that occurred. As for the gas given off when sodium is added to organic compounds, it could vary depending on the specific compounds present. It is possible that the gas given off could be hydrogen or a hydrocarbon gas. Again, without further testing and analysis, it is difficult to determine the exact gas produced.