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Bromocresol Green

Bromocresol Green

Bromocresol Green

(OP)
I need to know how much of a difference there is between Bromocresol Green .1% and Bromocresol Green .2%. How much does it matter. I know it indicates a differnce of .2 in pH, but does that really matter? I am titrating phosphate with sulfuric acid using Bromocresol Green as the indictor. And I need to know what I should order.

RE: Bromocresol Green

By .1%, do you mean 0.1%? If so, write it correctly.
By .2%, do you mean 0.2%? If so, write it correctly.

Re "it indicates a differnce of .2 [sic] in pH."
Wrong, the 0.2% indicator is easier to see.  Use twice as many drops if using 0.1% indicator instead (or half as many if vice versa).  It changes color at about pH 4.5.

I would order a pH meter with a combination electrode & pH 4 & 7 standards.

If you really must go by color change [no electricity?], both Fisher Sci. & Spectrum sell 0.1% bromocresol green in 500mL poly bottles for $25. & S&H + tax if applicable. Or, if using lots & lots, order the reagent powder and some isopropanol to dissolve it in (unless buying the water-soluble salt form).
http://www.fishersci.com
http://www.spectrumchemical.com

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