gota gift now how to use it

[wetchem]

Anyone familiar with this K1682 Taylor kit?
"Drop Test, Neutralizing Amines, Acid-Base Titration"

IN the kit:
It uses the R-0645 Total Alkalinity Indicator which is the same stuff as in R-0008-A in the K2006.
It then uses R-0869 as the titrant. The stuff is a dilute HCl; however I don't have a concentration for it. The stuff in the K2006 is R-0009-A which is a 0.12N-H2SO4 titrant. Now if I knew the concentration of the HCl in the R-0869 I can directly relate the two solutions - gota-luv-chemistry-n-math . I didn't have time to do this check myself in the lab - so I'm hoping that someone out there knows.

-wc

 

[257WbyMag]

This is a alkalinity test for steam/boiler units. It really has no applicability to swimming pool testing.

 

[wetchem]

This is a alkalinity test for steam/boiler units. It really has no applicability to swimming pool testing.

ahh... yes, thank you, I should have mentioned that we pulled it due to age and compliance reasons for boiler operations - however, it was stored in ideal conditions, hardly used by the lab staff (we prefer the burette and titrations with milliliters not drops... only used this in field at startup), but over a year old; thus, I hated to toss it (and the chemist in me likes the pretty colours ) when there was a use for the solutions that didn't have to meet some government dictate.

OK, small chemistry lesson... under normal conditions there is usually a 1:2 (molar) relationship between sulfuric acid (R-0009-A in the K2006 kit or... R-0687 in the industrial kits... same stuff, 0.12N sulfuric acid) and the hydrochloric acid unless one is after the oxidizing potential of the sulfuric acid (great for dissolving organic materials for nitrogen determination... but that's for a another day )

Now in this case... if I knew what the N (N = normality = one type of measurement for concentration) of the R-0869 solution is, then I would be able to relate the two solutions solutions (H2SO4 to HCl). Why use "normality" as a concentration unit... it is used to really (really) simplify the calculations required in industrial laboratories, or in this case, consumer chemistry.

for example: 1 drop of 1N-HCl will be the normality equivalent to 1 drop of 1N-H2SO4. Although the HCl is not a strong oxidizing acid as the sulfuric acid, and at this concentration the oxidizing potential is at such low levels as to be trivial, the results should be usable for TA with the correct math treatment.

Looking thru the Taylor website, they package the same chemicals with the same concentrations under several different part numbers... quite the setup for money makeing! Actually, I see this "repackaging" of the same compound all of the time... would be great if the U.S. had a required consumer chemistry in highschools. Look at this website with bleach v liqchlorine v calhypo. sigh. People (and sometimes companies) get ripped off all of the time because of this... just irritates me that companies get away with it!

-WC (Wet Chem(ist))

 

[chem geek]

For the purposes of the TA test, the oxidizing capabilities of the two acids are irrelevant. The acid is used simply to lower the pH by titrating until you get a color change from the dye which in the TA test represents 4.5 in pH. This occurs when the carbonate buffer system is essentially exhausted since the pH crashes rather quickly at that point.

So sulfuric acid, H₂SO₄ has both hydrogens count for its acidity even though the second one has a pKa of around 2. This is significantly lower than 4.5 that for practical purposes it's a strong acid for the purposes of the TA test. The 0.12N sulfuric acid is essentially 0.06M so equivalent to 0.12M (or 0.12N) hydrochloric acid. I can't find the concentration of the R-0869, however the instructions for the K-1682 kit say to subtract 2 from the number of drops added and then multiply by a conversion factor for expressing neutralizing amine. I think that the acid in R-0869 must be very weak because of the resulting ppm of the measured amines and the sensitivity of the test. This link of a similar titrant (but not from Taylor) is 0.01% HCl which would be 0.0027M (or 0.0027N). It would take over 44 times as much of this reagent to have the same effect as the R-0009.