Aldehydes and ketones
Read our general notes on Risk Assessment
Can I distinguish between an aldehyde and a carboxylic acid using Tollen's reagent? If not, how else can I distinguish between them (without using 2,4-DNPH)?
Corrie writes ...
In principle you could because the aldehyde should give a silver mirror whereas the carboxylic acid should not - provided it is not methanoic acid, which contains the aldehyde functional group as well the carboxylic acid functional group. Methanoic acid reacts very slowly with Tollen's reagent.
Carboxylic acids should give off carbon dioxide when a solution is added to little sodium hydrogencarbonate (or carbonate) solid or solution. Aldehydes should not react in this way, unless they contain a little acid impurity as a result of oxidation.
Risk assessment
Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any hazards, assess the risks from these hazards, and then decide appropriate control measures to reduce the risks. You must have these approved by those in authority in your school or college laboratory. Do not rely on what is said on this website.
For further guidance see our tutorial on Risk Assessment.
Rate this page or react
Share your views on this page, 0 ratings so far
updated: 14 November 2007
