Methyl red

 Methyl red (2-(N, N-dimethyl-4-aminophenyl) azobenzenecarboxylic corrosive), likewise called C.I. Corrosive Red 2, is a marker color that turns red in acidic arrangements. It is an azo color and is a dull red crystalline powder. Methyl red is a pH marker; it is red in pH under 4.4, yellow in pH more than 6.2, and orange in the middle of, with a pKa of 5.1. Murexide and methyl red are researched as promising enhancers of the sonochemical decimation of chlorinated hydrocarbon poisons.