As the Duke seeks somewhere to be alone with Annina, a group of senators and their wives detain him. Among them are Senator Delacqua and his supposed wife, and the Duke is taken aback at being introduced to a second Barbara. However, Annina identifies this "wife" for the Duke as the masked Ciboletta. The Duke goes along with Ciboletta's pretence, as he recalls the serenade he had sung to Barbara at previous carnival times. Delacqua pushes the supposed Barbara forward to put his own case for the position of the Duke's steward, but Ciboletta instead asks for a place for Pappacoda as the Duke's personal cook, and the Duke is only too ready to oblige her. Delacqua departs to join Barbara in Murano, leaving the Duke to take supper with Annina and Ciboletta. Caramello has sent away the servants, and he and Pappacoda wait on the trio personally in order to keep their eyes open for any unwelcome developments.