Indicators for Titrations (1 Viewer)

timeflies

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I'm a little confused as to what indicators are used for what titrations.

Wikipedia tells me:
Strong Acid, Strong Base: Phenolphthalein
Strong Acid, Weak Base: Methyl Orange
Weak Acid, Strong Base: Bromothymol Blue

However other sources are giving conflicting results and after coming across a question in a trial paper, I'm not sure what is right.
Can someone please clarify this for me?
 

HeroicPandas

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here are the pH ranges

Phenolph...: 8.3 -10
Methyl Orange: 3.1 - 4.4
Bromothymol: 6 - 7.6

For strong acid and strong base, the solution will become neutral (pH = 7) so bromothymol and phenols is best
For strong acid and weak base, the solution will come acidic (pH <7) so methyls is the best
For weak acid and strong base, the solution will become basic (pH>7), so phenol is the best, you can also use bromo

yeh for clarification, wiki is correct
 

iStudent

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Phenolph...: 8.3 -10
For strong acid and strong base, the solution will become neutral (pH = 7) so phenols is best
Can you explain that?
I thought for strong acid/strong base you either use bromo or litmus since equivalence point is near 7
(Unless the acid is in the burette and base is in the volumetric flask, ofc)
Or maybe I'm wrong... (I'm probably wrong since Wikipedia said so, lol)
 

someth1ng

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You can use anything that changes colour at or near pH of 7 because that's what would indicate that it has completely neutralised.
 

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