What's the plural form of heptanal? Here's the word you're looking for.
Answer
The noun heptanal can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be heptanal.
However, in more specific contexts, the plural form can also be heptanals e.g. in reference to various types of heptanals
or a collection of heptanals.
