How to Identify Organic Compounds | Questions and Answers
In the world, there are thousands of organic compounds in nature and animals. Organic compounds have a important role in wide scale applications. So we have to synthesis organic compounds or separate them from another compound. Thus we have to know, characteristics of different organic compounds.
There are lot of organic compound types which are categorized according to the elements which attached to the compound. As examples hydrocarbons, oxygen derivative organic compounds and more. These different types have different reactivity and physical properties.
Example
Identify ethanol and ethanoic acid
Ethanol is an alcohol compound and ethanoic acid is a carboxylic acid compound. Ethanoic acid reacts with NaOH, but ethanol does not. So, we can identify ethanol and ethanoic acid from that experiment.
Questions of organic compounds identifying
Try following questions to see whether you can identify two or more given compounds from various experiments, reactions and physical properties.
Example 2
How to identify ethanol from acetone?
Ketones are not oxidized like alcohols. Alcohol can be oxidized to aldehyde or carboxylic acid.
So, we can check the oxidation of ethanol and acetone for identification. Add acidic potassium permanaganate to ethanol and acetone and observe the solutions.
Purple colour of acidic potassium permanaganate is changed to colourless.
Example 3
Propose a method to identify aniline and phenol
Add sodium to aniline. Nothing is observed. Add sodium to phenol. Phenol will emit hydrogen gas.
Example 4
Identify aliphatic alcohols and phenols
Phenol reacts with aqueous NaOH and produce sodium phenoxide. But alcohols do not react with aqueous NaOH. Check the remaining NaOH in two solutions. You can see, in one solution (ethanol), all added NaOH is remaining after the reaction.
Example 5
How to identify alkanes from alkenes by liquid bromine?
Alkenes react with liquid bromine / CCl4 and produce alkyl halide compounds. So orange colour of bromine liquid is changed to colourless. But alkanes do not react with liquid bromine / CCl4 to any change.