"Perché il colore viola?"
why the correct answer is 'viola', with 'a' at the end? Shouldn't it go with 'o' because 'il colore' is masculine? Is it an exception or something?
Viola doesn't change.
- Colors ending in o have four forms: masculine and feminine, singular and plural.
- Many colors ending in e have two forms: singular and plural.
- Invariable colors have one form only.
This is from a Powerpoint explaining the colours, scroll down for the transcript: