Solutions and Indicators for Neutralization Titrations A. Standard Solutions: The standards solutions used as titrants for unknown w eak acids or bases are alw ays strong bases or acids, respectively. Standard titrant acids: dilute solutions of HCl, HClO 4 , or H 2 SO 4 . Standard titrant bases: dilute solutions of NaOH, KOH. The primary standards may not be strong acids or bases (., potassium acid phthalate, sodium oxalate, sodium bicarbonate).