[ziagemini]

Hello All,

I have two seems to be simple questions, hope i will get good help on this forum.

1. will there be any difference between pH curves if i do the titration(i.e. CaCO3 with HCl)using two different titrators. one with a closed vessel and the other with an open vessel. I have an open vessel titrator but i am not satidfied with my results will it make any difference if i do the same titration on a closed vessel.

2. Is there a way to check the concentration of my titrant. i have prepared 0.1M HCl from a stock solution by adding 8.3ml HCL into 91.7ml DW. But there are always some human errors. Are these errors negligible? Or if i want to chek the concentration how can I?

Hope to hear some good advice from all the professionals on this forum.

Regards!
Zia

[fledarmus]

Especially for HCl, there can be a lot of error just in the initial concentration of acid in your concentrated solution. It is always best to titrate your solution after diluting it. You can buy very accurate NaOH solutions to titrate against, or make your own - if you are very careful to avoid letting your NaOH absorb water, it is much easier to get an accurate weight of NaOH than it is to get an accurate measurement by volume of a concentrated HCl solution.

Of course, that all depends on how much accuracy you need. In many cases, plus or minus twenty percent is close enough, and you can get that even being pretty sloppy. In other cases, plus or minus 1 percent is too much error, and you must take great care in preparing and standardizing your solutions.

[Borek]

http://www.titrations.info/acid-base-titration-solution-standardization