Summary for sodium hydroxide analysis Discussion
sodium hydroxide analysis of alkaline zinc is discussed as a search for a replacement indicator after BDH 11-13 became unavailable. Philip Gormley asked what indicator to use for sodium hydroxide in alkaline non-cyanide zinc baths. K. Gendron suggested trying sulfo orange or phenolphthalein, noting he uses sulfo orange for cyanide solutions and phenolphthalein for alkaline cleaners, but he had not yet tested it on this bath. Bill Hemp described a titration method using barium carbonate, phenolphthalein, and 0.1N hydrochloric acid, with a pink-to-white endpoint. Lee Moss offered a different shop procedure using indigo carmine with 1.0N HCl and a conversion factor. A final reply said the shop abandoned indicators altogether and switched to a pH meter and stirrer for more repeatable results, using an endpoint pH of 11.2.
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 Gormley
plating services – Irvine ,Ayrshire, Scotland
2001
“The Chemical Analysis of Electroplating Solutions”
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“Analysis of Electroplating & Related Solutions”
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A. Try using sulfo orange
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eBay or
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or phenolphthalein
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Amazon [affil link]
. 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
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indicator.
4. Titrate with 0.1N hydrochloric acid, color change is pink to white.
5. mls. titrated x 1.06 = oz/gal.
Bill Hemp
tech 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
Nigel Gill
Aerospace – Glasgow, Scotland
April 7, 2019
Q. And how can I make the BDH 11-13 indicator by myself?
Which reagents are needed?
Benjamin Buettner
– 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
Paolo Scialuga
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,
Mark Lees
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.
Boris Siljanoski
– Perth, Western Australia
May 2, 2025