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The pH range of thymol blue (acid) is 1.2-2.8.. This pH range seems pretty useless. Generally, the sudden change in pH for SA-SB titration occurs in the range of 4-10; the sudden change in pH for SA-WB titration occurs in the range of 4-7, and the sudden change in pH for WA-SB titration occurs in the range of 8-10.

None of the ranges overlap with the pH range of thymol blue (acid), which is 1.2-2.8. When I found this indicator listed in my book, naturally I thought why this indicator is even listed here as its pH range seems pretty useless.

Are there any acid-base titrations/reactions where thymol blue (acid) is used as an indicator?

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    $\begingroup$ Being pH indicator and being pH indicator usable for acidobasic titrations are 2 different things. $\endgroup$
    – Poutnik
    Commented May 12, 2022 at 20:07
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    $\begingroup$ I guess you didn't check en.wikipedia.org/wiki/Thymol_blue ? $\endgroup$
    – Mithoron
    Commented May 12, 2022 at 21:25
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    $\begingroup$ @Mithoron thanks. I assume the comment was mainly for the OP. I have remembered there is an indicator with 2 transitions, but I have forgotten the one is thymol blue. Red 1.2->Yellow 2.8 + Yellow 8.0->Blue 9.6 $\endgroup$
    – Poutnik
    Commented May 13, 2022 at 7:38
  • $\begingroup$ @Mithoron Thymol blue is indeed a notable and useful indicator as it has a useful pH range of 8-9.6. However, I was wondering whether its other pH range of 1.2-2.8 is used in any acid-base titrations? $\endgroup$
    – tryingtobeastoic
    Commented May 13, 2022 at 8:02

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