Emily Bowen poured One Shot drain cleaner into a viola case owned by classmate Molly Young after she had found out the girl had begun dating her former boyfriend.
Ms Young was severely injured and the instrument was destroyed when she pulled her viola case from a shelf and the liquid poured from the case over her legs.
The attack has renewed calls for tighter controls on the sale of acid in the wake of a spate of attacks in England.
Bowen, now 18, previously admitted to recklessly and culpably pouring sulphuric acid into a viola case in the knowledge it would be removed from a shelf by Ms Young, causing sulphuric acid to spill onto her legs, all to her injury and permanent disfigurement, at Knox Academy, Haddington, East Lothian, on 29 September last year.
The victim was left “screaming in pain” as the acid drain cleaner burned her clothes and onto her skin during the incident in a music room at the school.
Bowen appeared back at Edinburgh Sheriff Court yesterday for sentencing where a sheriff described the acid attack as “utterly wicked” and sentenced her to 21 months in jail.
Sheriff Michael O’Grady QC said: “In the period leading up to these events you actually researched this topic and you of all people should have been aware of the potentially horrendous consequences for any young woman maimed by this mechanism.
“You have left a young woman to suffer a terrifying ordeal and she will be both physically and mentally scarred for the rest of her life.”
Sheriff O’Grady also banned Bowen from contacting her victim after sentencing her to a five year non-harassment order.
The sentence comes as four teenagers were arrested in north London on suspicion of being involved in acid attacks - the latest in a series of incidents in the UK capital. The Home Office has promised a series of new measures to crack down on the issue including proposals to ensure acid and other corrosive substances can be classed as dangerous weapons.
A spokesman for the Scottish Conservatives said: “There is a toughening up of sentences for acid attackers south of the border, and that should be looked at here too. It’s a relatively new type of crime, but it’s important the authorities catch up.
“The impact on victims is devastating, and that must be reflected in the sentences handed down.”
Previously the court was told both girls were acquaintances and both were members of the East Lothian school’s orchestra before the incident. Bowen played the clarinet while victim Molly played the viola.
The “talented musicians” fell out when the victim began going out with an ex-partner of the teenage attacker.
In a planned revenge attack, Bowen bought a bottle of drain cleaner online last September and hid it in her school locker.
She then sneaked into the school’s music room where all the pupil’s instruments are stored and poured the drain cleaner - which contained 91 per cent sulphuric acid - into Ms Young’s viola case.
But the plan to destroy her love rival’s instrument went wrong when the acid poured from the case onto the girl’s legs leaving her with horrific injuries and subsequently suffering from post traumatic stress disorder.
Prosecutor Aidan Higgins said both pupils were in sixth year and in the school orchestra at the time of the offence.
Mr Higgins added police had found evidence of Bowen researching acid attacks in the press and how long the attackers were being jailed for when they seized her phone.
The fiscal said: “The accused entered the music room and took down the girl’s viola case, opened it and poured a quantity of drain cleaner over the viola and inside the case. She then placed it back on the shelf.
“When the victim went into the strings room she was aware of an eggy smell. She then took down her case and she was immediately aware of red liquid spilling from the bottom of the case and landing on her right leg.
“She looked down and saw her tights were disintegrating and she was aware of an intense burning on her leg.”
Bowen was then identified as the culprit after a schoolboy had spotted her crouching down inside the deserted music room ten minutes before the incident occurred.
The victim, now 18, was subsequently rushed to Edinburgh Royal Infirmary for treatment to her injuries and eventually was transferred to St John’s hospital for plastic surgery treatment.
Police and the fire service were called in and the school was locked down due to chemicals being involved in the incident.
The court was also told Ms Young continues to suffer psychological problems and also has “shooting pains and nerve damage” due to the attack and has undergone painful laser treatment to the burns.
Yesterday, defence solicitor Jim Stephenson told the court Bowen had recently been diagnosed with autism and was suffering from depression.
Mr Stephenson added his young client “struggles to deal with things” and she has a “supportive family” but asked for a community order to be imposed so she can be monitored.
But Sheriff O’Grady told the acid attacker: “You should understand there is currently a very real public concern and fear about the emergence of this awful substance.
“It must be plain to anyone who resorts to acid for whatever purpose that the courts will not tolerate its possession or use for any criminal act.
“It is with considerable regret that I have come to the conclusion that nothing but a custodial sentence is appropriate.”