MODEL RELEASED. Alkaline titration using methyl orange. Endpoint of a titration using methyl orange to detect the neutralisation of an excess of alkali. Methyl orange turns pink in acid conditions. The conical flask initially contained an excess of alkali, and a measured volume of acid was being added by the burette (held in hand). The pink colour indicates that the volume of acid added has neutralised the alkali, allowing the previously unknown volume of alkali in the conical flask to be calculated.