How to Prepare Common Acid Solutions

How to Prepare Common Acid Solutions Common acid solutions can be prepared using the handy table below. The third column lists the amount of solute (acid) that is used to make 1 L of acid solution. Adjust the recipes accordingly to make larger or smaller volumes. For example, to make 500 mL of 6M HCl, use 250 mL of concentrated acid and slowly dilute to 500 mL with water. Tips for Preparing Acid Solutions Always add acid to a large volume of water. The solution may then be diluted with additional water to make one liter. Youll get an incorrect concentration if you add 1 liter of water to the acid. Its best to use a volumetric flask when preparing stock solutions, but you can use an Erlenmeyer flask if you only need an approximate concentration.  Because mixing acid with water is an exothermic reaction, be sure to use glassware capable of withstanding the temperature change (e.g., Pyrex or Kimax). Sulfuric acid is particularly reactive with water. Add the acid slowly to the water while stirring. Recipes for Acid Solutions Name / Formula / F.W. Concentration Amount/Liter Acetic Acid 6 M 345 mL CH3CO2H 3 M 173 F.W. 60.05 1 M 58 99.7%, 17.4 M 0.5 M 29 sp. gr. 1.05 0.1 M 5.8 Hydrochloric Acid 6 M 500 mL HCl 3 M 250 F.W. 36.4 1 M 83 37.2%, 12.1 M 0.5 M 41 sp. gr. 1.19 0.1 M 8.3 Nitric Acid 6 M 380 mL HNO3 3 M 190 F.W. 63.01 1 M 63 70.0%, 15.8 M 0.5 M 32 sp. gr. 1.42 0.1 M 6.3 Phosphoric Acid 6 M 405 mL H3PO4 3 M 203 F.W. 98.00 1 M 68 85.5%, 14.8 M 0.5 M 34 sp. gr. 1.70 0.1 M 6.8 Sulfuric Acid 9 M 500 mL H2SO4 6 M 333 F.W. 98.08 3 M 167 96.0%, 18.0 M 1 M 56 sp. gr. 1.84 0.5 M 28 0.1 M 5.6 Acid Safety Information You should always wear protective gear when mixing acid solutions. Be sure to wear safety goggles, gloves, and a lab coat as well. Tie back long hair and make sure your legs and feet are covered by long pants and shoes. Its a good idea to prepare acid solutions inside the ventilation hood because the fumes can be noxious, particularly if you are working with concentrated acids or if your glassware isnt absolutely clean. If you do spill acid, you can neutralize it with a weak base (safer than using a strong base) and dilute it with a large volume of water. Why Arent There Instructions for Using Pure (Concentrated) Acids? Reagent-grade acids typically range from 9.5  M (perchloric acid) to 28.9 M (hydrofluoric acid). These concentrated acids are extremely dangerous to work with, so they are usually diluted to make stock solutions (instructions included with the shipping information). The stock solutions are then further diluted as needed for working solutions.