methyl orange is an indicator with a ka of
Methyl orange In an acid, it is reddish and in alkali, it is yellow. Methyl orange has a pKa of 3.47 in water at 25 °C (77 °F).[2]
Potassium bitartrate Potassium bitartrate, also known as potassium hydrogen tartrate, with formula KC4H5O6, is a byproduct of winemaking. In cooking it is known as cream of tartar. It is the potassium acid salt of tartaric acid (a carboxylic acid). It can be used in baking or as a cleaning solution (when mixed with an acidic solution such as lemon juice or white vinegar).