Methyl orange

methyl orange
    n 1: an azo dye used as an acid-base indicator; used for
         titrations involving weak bases
    

Methyl \Meth"yl\, n. [See {Methylene}.] (Chem.)
   A univalent hydrocarbon radical, {CH3-}, not existing alone
   but regarded as an essential residue of methane, and
   appearing as a component part of many derivatives; as, methyl
   alcohol, methyl ether, methyl amine, etc. [Formerly written
   also {methule}, {methyle}, etc.]
   [1913 Webster]

   {Methyl alcohol} (Chem.), a light, volatile, inflammable
      liquid, {CH3.OH}, obtained by the distillation of wood,
      and hence called {wood alcohol} or {wood spirit};
      tecnically referred to as {methanol}; -- called also
      {methol}, {carbinol}, etc.

   {Methyl amine} (Chem.), a colorless, inflammable, alkaline
      gas, {CH3.NH2}, having an ammoniacal, fishy odor. It is
      produced artificially, and also occurs naturally in
      herring brine and other fishy products. It is regarded as
      ammonia in which a third of its hydrogen is replaced by
      methyl, and is a type of the class of substituted
      ammonias.

   {Methyl ether} (Chem.), a light, volatile ether {CH3.O.CH3},
      obtained by the etherification of methyl alcohol; --
      called also {methyl oxide} or {dimethyl ether}.

   {Methyl green}. (Chem.) See under {Green}, n.

   {Methyl orange}. (Chem.) See {Helianthin}.

   {Methyl violet} (Chem.), an artificial dye, consisting of
      certain methyl halogen derivatives of rosaniline.
      [1913 Webster]
    

Helianthin \He`li*an"thin\, n. [Prob. fr. L. helianthes, or NL.
   helianthus, sunflower, in allusion to its color.] (Chem.)
   An artificial, orange dyestuff, analogous to tropaolin, and
   like it used as an indicator in alkalimetry; -- called also
   {methyl orange}.
   [1913 Webster]