Dakin's solution is: (A) 0.5% NaOCl, (B) 2.5% NaOCl, (C) 1.25% NaOCl, (D) 5.2% NaOCl
Answer is A. NaOCl as a buffered 0.5% solution was recommended for irrigation of wound during world war I by Dakin. Coolidge introduced NaoCl to endodontics.