Australia's Science Forum

I may be missing something in my maths but can anyone help me with a problem regarding Hydrochloric Acid. Our concentrate come as 32% which is then described in manuals as 10 M.

I can't work out why, if the Molecular weight of HCl is 36.46 why 10M HCl should not be 36% and the 32% concentration about 8.8M.

Our senior chem has just started titrations and I'm being told my stock solution is out and am trying to work out why.

The chemistry teacher can't help me, his comment is "they may have just labelled it wrong!"

Thanks for any information,

Wendy

Hi Fibreweb,

If you do a search of the forums you will find an old entry from October last year dealing with this question.

Look up Stock Hcl Solution .

Lorrae

Hi Wendy,

Just to fast track you regarding the HCl post in the forum rae has indicated.

HCl can have two concentrated forms (Concentrations)

HCl 32% which is 10M

HCl 36% which is 12M

The later is what we call fuming Hydrochloric Acid because the H[sup]+[/sup] and Cl[sup]-[/sup] will escape more visible than the 32%.

This is where things are getting mixed up by the sounds of things.

The above will get you out of trouble.

Cheers,

Robb....

This is an old topic but I have the same scenario here where the Chem teacher is puzzled why the 1 M HCL needs almost twice as much to balance the 1 M NaOH . He's sure the NaOH must be right as its derived from a solid but is querying the HCL concentration .

We have 32% stock but its very old by the looks of the bottles and the Date is unreadable . Does this stuff loose its strength with a long shelf life ?