Learn Italian: Non avresti mica ignorato un equivoco così grande? - You wouldn't have ignored such a big misunderstanding, would you?

In a negative question, mica expresses doubt or asks for confirmation, hoping for a negative answer. It acts like the English tag question "...would you?" or "Don't tell me you...". The speaker is essentially saying "You wouldn't have ignored it, right?".

Where should I place mica when using compound tenses like the past conditional?

Just like with the passato prossimo, when using compound tenses, the particle mica is typically placed directly between the auxiliary verb (here, avresti) and the past participle (ignorato).

Why use the past conditional (avresti ignorato) here instead of a normal past tense?

The past conditional is used because the action is hypothetical. The speaker isn't asking a factual question about what the person definitely did, but rather asking what they would have done under certain circumstances.

Why is it un equivoco così grande instead of un così grande equivoco?

While English says "such a big misunderstanding", Italian usually structures this as "a misunderstanding so big". When using così (so) plus an adjective, the phrase almost always goes directly after the noun it modifies.