reaktsioonil

Reaktsioonil is the adessive singular form of the Estonian noun reakt­sioon, meaning reaction. In usage, reaktsioonil denotes a location, context, or state related to a reaction, and it appears in scientific writing as well as in broader descriptions of processes that involve a reaction or response.

Etymology and meaning: The word reakt­sioon comes from Latin reactio and entered Estonian through German. The adessive form reaktsioonil is used to specify “on/at the reaction” or “in the reaction” depending on the context, aligning with Estonian case grammar to link a noun to the surrounding clause.

Usage and examples: In chemistry, reaktsioonil is commonly used to describe phenomena that occur within the reaction. Examples include: Reaktsioonil tekkivad kõrvalproduktid võivad mõjutada lõpptoote kvaliteeti. (Side products formed in the reaction may affect product quality.) Reaktsioonil osalevad ained peab olema puhtad. (The substances participating in the reaction must be pure.) The term can also appear in more general contexts to indicate involvement or occurrence related to a process, for instance in discussions of a social or biological response.

Grammatical notes: Reaktsioonil is the singular adessive form; the plural would be reakt­sioonidel. It is typically used with nouns or participial phrases that describe what happens on or within the reaction or process. Although closely related to other case forms such as reaktsioonis (in the reaction) or reaktsiooni (of the reaction), reaktsioonil emphasizes location or context rather than containment or movement.

See also: reakt­sioon, reaktsioonis, reaktsiooni

Reaktsioonil thus serves as a practical grammatical tool in Estonian to tie statements to the occurrence or context of a reaction, whether chemical, physical, or conceptual.