Thursday, March 3, 2022

Why is methyl orange used in titration?

In chemistry, methyl orange is often used as a pH indicator because it provides easy and clear color changes across its pH range. It's broadly used in acid titrations since it changes color at the pH of a midi-strength acid.

Methyl orange turns red in an acidic environment (pH is less than 4.4), while in a basic environment (pH is greater than 6.2), it turns yellow, with a pKa of 5.1. It is normally used as an acid-base indicator.

Why is a methyl orange indicator used in titration?

Methyl orange is used in titrations with acidic solutions, because it has such a narrow range, allowing it to be used as an indicator. Its clear and vivid color change makes it a more suitable indicator for titration experiments. Generally, drops of titrant can be added to the analyte until the desired color is reached, indicating the end of the titration.

For laboratory practicals, preparation and use of methyl orange indicator is quite easy. If you want to find the equivalence point between a known titrant and an analyte, you can use an indicator.

Most mineral acids can be titrated with it, but not organic acids. It can be used to titrate an acid with a moderately weak base like sodium carbonate (Na2CO3). When used in titrations of strong acid and weak base, methyl orange is quite accurate, as its equivalence point is below pH 7.0.


Frequently Asked Question (FAQ):


Methyl orange indicator is used in which titration?

Generally Methyl orange is suitable for strong acid-weak base titration since it will change sharply at the equivalence point.

When should you use the methyl orange indicator?

Methyl orange indicator is used when the equivalence point of the acid-base titration is around at pH range of 3 to 5. It turns red in an acidic medium, while it turns yellow in basic conditions.

Why is methyl orange and phenolphthalein not a suitable indicator for complexometric titration?

Methyl orange and phenolphthalein is not suitable indicator for complexometric titration, because they both are acid-base indicator that reacts to pH, whereas complexometric titration works on different principle in which the formation of a colored complex is used to indicate the endpoint.


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