She was rushed to the general hospital here with severe burns on face.
After first-aid, she was referred to Chennai for further treatment.
The assailant also sustained burn injuries on his hand and was admitted to government hospital here and has been arrested on a complaint from the woman's father, police said.
The man and the woman had studied their B.Tech in a private college in Karaikal together when he had fallen in love with her and wanted to marry her. But, she had refused his proposal.