How many letters does the top answer for “a salt of the hypothetical dichromic acid” have?

The most common answer is bichromate (10 letters).

Crossword clue: a salt of the hypothetical dichromic acid

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

bichromate 10 letters wn-def

a salt of the hypothetical dichromic acid

dichromate 10 letters wn-def

a salt of the hypothetical dichromic acid

a salt of a hypothetical thallic acid. 60% similar → thallate