Why hydrochloric acid cannot be made up as an accurate (standard) solution from pure hydrogen chloride gas?
Jenkin replies: Imagine trying to do this! The solubility of hydrogen chloride, as with any gas, varies according to the temperature and pressure. How would you know when your solution was of the required concentration? One method that has been used is depends on the fact that an aqueous solution of HCl loses either water or HCl gas on boiling until it reaches a certain composition, which is constant. This solution is called constant-boiling point HCl and its composition at various pressures has been determined with great accuracy. For example, at 1 atm pressure, 180.193 grams of the mixture contains exactly 1 mole of HCl, so a solution of known concentration can be made by dilution. For most of us, it is much simpler to make a solution of approximately the required concentration and then standardise it by titration with a standard alkali. Risk assessment Before attempting any practical work based on the advice and suggestions on this website, you must do the following. Identify any ha
Related Questions
- Why are hydrochloric acid and hydrogen chloride listed separately in the List of Regulated Substances at 40 CFR ยง68.130?
- Why hydrochloric acid cannot be made up as an accurate (standard) solution from pure hydrogen chloride gas?
- What is Magnesium metal plus hydrochloric acid to form magnesium chloride and hydrogen gas?
