Question: How to make phenolphthalein TEST solution?
Ans: Dissolve 10.0 g of phenolphthalein powder in 750 mL of ethanol and dilute to 1 L with distilled water. Add 0.1 N sodium hydroxide (NaOH) solution dropwise to the first permanent faint pink end point. Color and pH range: colorless 8.3-10.0 red.
OTHER PH INDICATOR:
Thymolphthalein RXSOL-60-6605-733 is a phthalein dye used as an acid–base (pH) indicator. Its transition range is around pH 9.3–10.5. Below this pH, it is colorless; above, it is blue.
Phenolphthalein's RXSOL-60-6201-100 common use is as an indicator in acid-base titrations. It also serves as a component of universal indicator, together with methyl red, bromothymol blue, and thymol blue.
Phenolphthalein (pH indicator) indicator range below pH 8.3 above pH 10.0 ::: PINK COLOUR
8.3 ⇌ 10.0
Methyl red RXSOL-69-4935-270 (2-(N,N-dimethyl-4-aminophenyl) azobenzenecarboxylic acid), also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder.
Methyl red is a pH indicator;
it is red in pH under 4.4, yellow in pH over 6.2
4.4 ⇌ 6.2
Bromothymol blue RXSOL-60-6295-125 also known as bromothymol sulfone phthalein and BTB
Bromothymol blue is a pH indicator.
it is yellow in pH under 6, Blue in pH over 7.6
6 ⇌ 7.6