Standardizing NaOH

[Sebbass69]

Hi everyone

I have a quick question I hope you all can answer. I'm titrating some HNO3 to determine concentration, however I have not standardized my NaOH solution. I'm looking for a suitable standardizing agent, and I've come across a few. KHP seems to be the most common

but oxalic acid and hydrochloric acid are also listed. If I was to buy a standardized solution of HCl, would that be suitable for standardizing my NaOH? I can buy standardized NaOH but doesn't it frequently absorb moisture and CO2 from the air thereby altering concentration and throwing off the titration?

Thank you,

~Sebastian

[mississippichem]

Hi everyone

I have a quick question I hope you all can answer. I'm titrating some HNO3 to determine concentration, however I have not standardized my NaOH solution. I'm looking for a suitable standardizing agent, and I've come across a few. KHP seems to be the most common

but oxalic acid and hydrochloric acid are also listed. If I was to buy a standardized solution of HCl, would that be suitable for standardizing my NaOH? I can buy standardized NaOH but doesn't it frequently absorb moisture and CO2 from the air thereby altering concentration and throwing off the titration?

 

~Sebastian

 

HCl or KHP will work. I like KHP because it is technically better to standardize a strong acid/base against a weak acid/base. One can be more certain that all the KHP has been consumed as all "strong electrolytes" are not equally strong and the precise value of their acid equilibrium constants is not firmly established out in the small decimal places. Plus KHP has two ionizable protons which makes for a more rigorous titration curve if you are planning on plotting a curve. Two endpoints are more analytically sound than just one.

 

NaOH is hygroscopic yes, but so is KHP to a small degree. Just keep your burette covered and be sure to make solutions with a volumetric flasks and not in graduated cylinders. If you haven't done much analytical work before, remember the goal is to be as precise and consistent as possible. The word "anal" is inside the word "analytical".

Edited December 28, 2010 by mississippichem