Up to ten men, some with hoods over their faces, attacked her and filmed it on mobiles.
The gang — including Miguel Almeida, 22, and Opeyemi Ismail, 20 — allegedly fled laughing as the chemical left her screaming in agony.
The jury yesterday listened to a harrowing 999 call of the girl’s screams as a neighbour called an ambulance.
The victim was picked on because she previously had consensual sex with some of the gang, it was claimed.
Prosecutor Rosina Cottage told the jury: “They thought she was, to use the words of a number of these defendants, a ho — a whore — a dirty ho who was asking for it.”
Rogel McMorris, 18, allegedly lured the girl to a derelict house in Tottenham, North London, in January, where the ten were waiting.
The teenager, who has a mental age of about eight, had skin peeling off her face, chest and genital area because her tormentors poured water on her, intensifying the burning, jurors heard.
As the unnamed girl screamed, the gang laughed and ran away, said prosecutor Rosina Cottage.
One defendant, Bradley Daley-Smith, apparently later told a friend: 'She was a ho and she deserved it.'
Seven men are accused of the rape at a derelict house in Tottenham, north London, in January.
Two hours later, neighbour Helen Riddell heard 'frantic screams'.
She found the alleged victim covered in a white powder with pink patches on her peeling black skin.
In Ms Riddell's 999 call, played to the jury, the girl's cries could clearly be heard. She told police she had had sex with 'about ten males' without her consent.
'Naked, screaming and crying, she was in no position to make up a cover story,' said Ms Cottage.
She was left with burns on half her body and 'severely disfigured', despite months of operations.
She could not speak for a month after the alleged attack.
She was probably picked on because she had previously agreed to sex with Mr Hendricks and Daley-Smith in a bid to be popular, added Ms Cottage.
McMorris, of Stockwell, South London; Daley-Smith, 22, and Miguel Almeida, 22, both of Edmonton, North London; Jason Brew, 19, and Bruno Abrantes, 24, both of Tottenham; Hector Muaimba, 20, of Walthamstow, East London; and Opeyemi Ismail, 20, of Leyton, East London all deny two counts of rape. Five also deny GBH with intent. The trial at Wood Green Crown Court continues.