methyl orange

American  

noun

Chemistry.

1. an orange-yellow, slightly water-soluble powder, C 1 4 H 1 4 N 3 NaO 3 S, used chiefly as an acid-base indicator.

---

Etymology

Origin of methyl orange

First recorded in 1880–85

Example Sentences

The equilibrium in a solution of the acid-base indicator methyl orange, a weak acid, can be represented by an equation in which we use HIn as a simple representation for the complex methyl orange molecule:

From Textbooks • Feb. 14, 2019

When we add acid to a solution of methyl orange, the increased hydronium ion concentration shifts the equilibrium toward the nonionized red form, in accordance with Le Châtelier’s principle.

From Textbooks • Feb. 14, 2019

The anion of methyl orange, In−, is yellow, and the nonionized form, HIn, is red.

From Textbooks • Feb. 14, 2019

Pipette off 50 cubic centimeters into a 200 cubic centimeter beaker, dilute slightly with distilled water, add a few drops of methyl orange indicator and titrate with normal acid.

From Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. by Thomssen, E. G.

If borax is present the carbon dioxide is boiled off after neutralizing exactly to methyl orange; cool, add mannite and phenolphthalein and titrate the boric acid with standard alkali.

From Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. by Thomssen, E. G.