This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'The fluoride ion concentration in aqueous solution of acidulated phosphate fluoride solution is- \nSelect and explain. \nA. 1.32%, B. 2.23%, C. 1.23%, D. 2.32%', 'role': 'user'}, {'content': "Answer: C \nExplanation: An aqueous solution of acidulated phosphate\xa0fluoride is prepared by dissolving 20 grams of\xa0sodium fluoride in 1 liter of 0.1\xa0M phosphoric\xa0acid and to this is added 50% hydrofluoric\xa0acid to adjust the pH at 3.0 and fluoride ion\xa0concentration at 1.23%. It is also called as\xa0Brudevold's solution.", 'role': 'assistant'}]