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