A new department store opened near us today, and I noticed that they were selling 'concentrated formic acid' as a limescale remover. I purchased 400ml
for testing, and, after a quick acid/base titration using litmus blue indicator it was found to be of 13.02M concentration (13.02M/L), with some error
perhaps as I used a very strong base, NaOH, against the formic acid, which is comparatively weak. I also took a rough density measurement using a Mohr
pipette and my shitty drug dealer balance, and it was found to have a density of 1.06g/ml.
I used to be able to do this, but now I've just confused myself and some of the information on the web is incomprehensible from my perspective . .
.using this data above, how do I calculate the v/v and w/v percentages of my acid?
[Edited on 6-4-2012 by Hexavalent]peach - 6-4-2012 at 10:55
The 'neutral' (equilivance) point of the titration is basic, because it's a weak acid with a strong base.
If you used blue papers, I would assume you drove it down until the paper turned red, which means you'll have overshot on the addition.
To be more sure, check the back of the pack carefully as it may have it's percentage written on it. Failing that, google the brand name and include
the word 'msds', as the safety sheet for the product often lists the percentage of corrosive or otherwise harmful things in the mixture.
[Edited on 6-4-2012 by peach]Hexavalent - 6-4-2012 at 10:57
I used the litmus blue powder, which is dissolved into water to use as an indicator in the same fashion as phenolphthalein.
It's sometimes easier if you say 'acid indicating' or 'alkali indicating', as I'm still unsure which you mean.
If the powder was blue, it'll indicate red - acidic. Whereas phenolphthalein (a word I still struggle to spell), indicates alkali.
Litmus blue is blue under basic conditions, and red under acid.
When purchased, the powder was blue. It was dissolved in water, and upon addition to the aliquot of acid, it turned red. Base was added until it
permanently changed back to a faint blue.
[Edited on 6-4-2012 by Hexavalent]Hexavalent - 6-4-2012 at 11:18
[Edited on 6-4-2012 by peach]Hexavalent - 6-4-2012 at 11:28
Thanks for your help, as mentioned the titration was done very quickly, using a bench 1M NaOH solution and a rough aliquot of acid with probably some
level of overshoot.
If anyone's interested, it was 'The Range' shop I got it from . . .I was also tempted to get some sodium bisulfate and dichloroisocyanuric acid from
the pool section No NaBr, though, damn!!peach - 6-4-2012 at 11:38
I think I've seen the same stuff in B&Q too.
After some more googling, I discovered Rodine is a common series of acid corrosion inhibitors. It's some proprietary additive, they're called P3 and
the one for formic is 85 I think.
Shoot them an email, telling them you've just drunk the bottle and need to know asap, and let us know. Hexavalent - 6-4-2012 at 11:46
Hmm . . .I think they'd be inclined to take further action if I did that
How could I pose the question without getting them concerned?peach - 6-4-2012 at 13:02
Quote:
inclined to take further action
A personalised stomach pump from Henkel, with Henkel on the tube.
Just ask for it.
They have to give you it as a legal thing to ensure it's handled safely. The website actually suggests you read it prior to using the product.
Although they may only have to give you it if you have bought the product. Not entirely sure about the fine details there, which may
vary from place to place. Most companies list them up since it'd be a pain trying to collect receipts to then hand out the msds.CHRIS25 - 17-7-2012 at 01:46
Hexavalent and Peach, thanks for the question Hexavalent, you've just solved my headache with this question. The websites that have been recently
mentioned regarding maths are excellent, so just giving gratitude to the forum really.
No NaBr, though, damn!!
