The girl was returning home on her scooty when the accused, Mukesh Aheer (21), along with an accomplice threw acid on her near a railway station flyover here, police said.
"The accused was arrested this evening. The accused said that he wanted to have a relationship with the girl but she rejected. He is being further interrogated at the Mundawar police station," Superintendent of Police Vikas Kumar said.
The girl received burn injuries on face and left hand.
She is being treated at a government hospital where her condition is stated to be stable, the SP said.