Acid-base equilibria
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What is screened methyl orange?
How many components are in it?
What are they?
Igloo writes
Although methyl orange is an ideal indicator for titrations involving strong acids and weak bases, many people using it find the end-point difficult to judge, and prefer to use “screened” methyl orange, which comes in several varieties. If you refer to Table 6.6 of your Nuffield Data Book you will note a reference to Methyl Orange - Xylene Cyanole solution. This is perhaps the best known type of screened methyl orange (and I do not know the proportions in which these dyes are mixed), but another variety which I have used consists of mixing 0.1 g of bromocresol green and 0.2 g of methyl orange in 100 g of water.
Since there are different versions of screened methyl orange I cannot therefore give you a definitive answer to your question.
In all cases screened methyl orange is purple in acid, green in alkali and “grey” at the end point.
Risk assessment
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updated: 21 August 2003
