Methyl orange is a pH indicator frequently used in titration because of its clear and distinct color variance at different pH values. Methyl orange shows red color in acidic medium and yellow color in basic medium. Because it changes color at the pKa of a mid strength acid, it is usually used in titration for acids.

Application

Methyl Orange Indicator Solution: Dissolve 0.1 g of methyl orange in 80 ml of water and add sufficient ethanol (95 percent) to produce l00 ml. Complies with the following test. SENSITIVITY - A mixture of 0.1 m] of the solution and 100 ml of carbon dioxide-free water is yellow.