Why methanal is called formaldehyde, ethanal is called acetalaldehyde and pentanal is called valeradehyde?? Thanks

1 Answer
Dec 23, 2017

That's the difference between the historical development of chemistry and the development of consistent nomenclature.

Explanation:

In "the early days" chemicals were often named in relation to how they were derived, or even where. Even the elements retain ancient terminology in their symbols, like #Fe# (ferro) for Iron and #Hg# for Mercury.

As this example illustrates, we have even systematized the previous functional group designations (aldehydes are now represented by the suffix "al" instead of the whole word). As more and more new compounds (and elements) were discovered or made, a consistent system of nomenclature became even more necessary to transfer knowledge in textual forms. The International Union of Pure and Applied Chemistry (IUPAC) was set up to define the nomenclature rules for all of chemistry. https://iupac.org/

In this case, "formaldehyde" is named that because it was produced by a reaction with "formic acid".

Formic acid was first isolated from certain ants and was named after the Latin formica, meaning “ant.”
https://www.britannica.com/science/formic-acid

The others can also be researched following "History of Chemistry" (or the compound) instead of the relevant reactions that are usually linked to compound names in searches.