What is "methyl orange"

Helianthin \He`li*an"thin\, n. [Prob. fr. L. helianthes, or NL. helianthus, sunflower, in allusion to its color.] (Chem.) An artificial, orange dyestuff, analogous to tropaolin, and like it used as an indicator in alkalimetry; -- called also methyl orange.

n. (context chemistry English) An azo dye used as an acid-base indicator for titrations involving a weak base

n. an azo dye used as an acid-base indicator; used for titrations involving weak bases

Methyl orange is a pH indicator frequently used in titrations because of its clear and distinct colour change. Because it changes colour at the pH of a midstrength acid, it is usually used in titrations for acids. Unlike a universal indicator, methyl orange does not have a full spectrum of colour change, but has a sharper end point. Methyl orange shows orange colour in acidic medium and yellow colour in basic medium.