The woman and her 15-year-old daughter were taken to a hospital in Agra after the incident early today, from where they were referred to Delhi's Safdarjung Hospital, police said, adding condition of the mother is stated to be serious.
Meanwhile, police have arrested the accused Raja based on the information provided by the woman's son, they said.
The boy told police that Raja, after entering into an argument with his mother last night, sneaked into their house in the wee hours today and threw acid on the mother-daughter duo.