How many letters does the top answer for “a salt of boric and silicic acids” have?

The most common answer is borosilicate (12 letters).

Crossword clue: a salt of boric and silicic acids

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

borosilicate 12 letters wn-def

a salt of boric and silicic acids

a salt of silicic acid. 75% similar → silicate

a salt or ester of boric acid 60% similar → borate

a salt or ester derived from silicic acid 50% similar → silicate