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Sodium hydroxide analysis of alkaline zinc
Q. What indicator do you suggest I use for analysis of sodium hydroxide in alkaline non cyanide zincs? The one used at present is BDH 11-13 but this is no longer available.
Philip Gormleyplating services - Irvine ,Ayrshire, Scotland
2001
by Terrance H Irvine
on eBay or Amazon
or AbeBooks
(affil link)
by Langford & Parker
on Amazon
or AbeBooks
(affil link)
A. Try using sulfo orange ⇦ on eBay or Amazon [affil links] or phenolphthalein ⇦ on eBay & Amazon [affil links] . I use the sulfo-orange for cyanide based solutions. It might work. I use the phenolphthalein for alkaline cleaners.
I'm not at work until Tuesday, at which time, if you want I can try a couple of experiments and get back to you.
K. Gendron- Trenton, ON, Canada
A. 1. 5 ml. sample into a 250 ml. flask.
2. Add 25 ml. 20 % barium carbonate.
3. Add 3 drops phenolphthalein ⇦ on eBay & Amazon [affil links] indicator.
4. Titrate with 0.1N hydrochloric acid, color change is pink to white.
5. mls. titrated x 1.06 = oz/gal.
Bill Hemptech svc. w/ chemical supplier - Grand Rapids, Michigan
A. In response to the NaOH Titration procedure of Alkaline Zinc At our shop we use 5 ml sample 20 ml water A few specks of Indigo Carmine Indicator Titrate with 1.0N HCl from yellow to blue mls titrated * 0.95 = OZ/GAL * 7.5 = gms/lt
Lee Moss- Calgary, Alberta, CANADA
A. We gave up on indicators and now use a pH meter and stirrer this gives more repeatable results. End point pH 11.2
Martin Trigg-Hogarth
surface treatment shop - Stroud, Glos, England
A. BDH 11-13 indicator is actually pretty easy to make yourself ... only 2 reagents needed
I have been making my own for years
Aerospace - Glasgow, Scotland
April 7, 2019
Q. And how can I make the BDH 11-13 indicator by myself?
Which reagents are needed?
- Newhouse, Thuringia, Germany
Q. Good morning,
I would like to know the recipe for the preparation of the BDH 11-13 that I used but, at the end of the product, I was no longer able to obtain it from my supplier who did it in his laboratory.
Paul from Torino Italia
Surfaces treatment - Torino Piemonte Italia
A. Hi Paolo,
The compound used in BDH 1113 indicator is 4-(4-Nitrophenylazo)resorcinol.
So, dissolve ~1% m/v in ethanol.
You can get 4-(4-Nitrophenylazo)resorcinol from Fisher Scientific.
Best Regards,
aerospace - A not so warm rock in the irish sea
Tropaeolin OOO Indicator
1.0N Hydrochloric Acid
Pipette 5 mL sample into a 50mL Erlenmeyer Flask. Add 5-9 drops Tropaeolin OOO. Titrate with 1.0 N Hydrochloric Acid from an Orange to yellow End-Point.
You'll have to experiment with exact amount of indicator to use, depends how strong the indicator solution is. You may find too much or too little indicator may make the endpoint hard to catch.
It's important to constantly agitate the flask as this reaction I find is a little bit lagging.
- Perth, Western Australia
May 2, 2025
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