Methyl orange

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Methyl orange is a pH indicator frequently used in titrations due to its clear and distinct color change. It is a weak acid that dissociates in water to form orange neutral molecules and red anions.

Chemical Properties

Methyl orange has the chemical formula C_14H_14N_3NaO_3S. It is an azo dye, which means it contains the functional group R-N=N-R', where R and R' can be either aryl or alkyl. The structure of methyl orange includes a benzene ring, which is a common feature in many organic compounds.

Color Change

Methyl orange changes color at a pH of 3.1 to 4.4. In acidic conditions, it appears red, while in alkaline conditions, it turns yellow. This makes it particularly useful for titrations involving strong acids and weak bases.

Applications

Methyl orange is widely used in analytical chemistry for titrations. It is also used in the textile industry as a dye. In laboratories, it serves as a pH indicator to determine the acidity or basicity of a solution.

Safety and Handling

Methyl orange should be handled with care. It can be harmful if ingested or inhaled and may cause skin and eye irritation. Proper laboratory safety protocols should be followed when handling this chemical.

See Also

• pH indicator
• Titration
• Azo dye
• Analytical chemistry