How many letters does the top answer for “a salt formed by the union of arsenious acid with a base.” have?

The most common answer is arsenite (8 letters).

Crossword clue: a salt formed by the union of arsenious acid with a base.

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

arsenite 8 letters web-def

A salt formed by the union of arsenious acid with a base.