Éclaircir belong to the 2
nd group. Éclaircir is a very common french verb.
Éclaircir is conjugated the same way that verbs that end in :
-ir
Éclaircir is conjugated with
auxiliary avoir.
Éclaircir verb is
direct transitive.
French verb éclaircir can be conjugated in the reflexive form:
S'éclaircir
Éclaircir verb is a direct transitive verb, so passive voice can be used.