n. 氢氧化钠

Sodium \So"di*um\, n. [NL., fr.E. soda.] (Chem.)
A common metallic element of the alkali group, in nature
always occuring combined, as in common salt, in albite, etc.
It is isolated as a soft, waxy, white, unstable metal, so
highly reactive that it combines violently with water, and to
be preserved must be kept under petroleum or some similar
liquid. Sodium is used combined in many salts, in the free
state as a reducer, and as a means of obtaining other metals
(as magnesium and aluminium) is an important commercial
product. Symbol Na ({Natrium}). Atomic weight 22.990.
Specific gravity 0.97.

{Sodium amalgam}, an alloy of sodium and mercury, usually
produced as a gray metallic crystalline substance, which
is used as a reducing agent, and otherwise.

{Sodium carbonate}, a white crystalline substance,
{Na2CO3.10H2O}, having a cooling alkaline taste, found in
the ashes of many plants, and produced artifically in
large quantities from common salt. It is used in making
soap, glass, paper, etc., and as alkaline agent in many
chemical industries. Called also {sal soda}, {washing
soda}, or {soda}. Cf. {Sodium bicarbonate}, and {Trona}.


{Sodium chloride}, common, or table, salt, {NaCl}.

{Sodium hydroxide}, a white opaque brittle solid, {NaOH},
having a fibrous structure, produced by the action of
quicklime, or of calcium hydrate (milk of lime), on sodium
carbonate. It is a strong alkali, and is used in the
manufacture of soap, in making wood pulp for paper, etc.
Called also {sodium hydrate}, and {caustic soda}. By
extension, a solution of sodium hydroxide.


Ternary \Ter"na*ry\, a. [L. ternarius, fr. terni. See {Tern},
a.]
1. Proceeding by threes; consisting of three; as, the ternary
number was anciently esteemed a symbol of perfection, and
held in great veneration.

2. (Chem.) Containing, or consisting of, three different
parts, as elements, atoms, groups, or radicals, which are
regarded as having different functions or relations in the
molecule; thus, sodic hydroxide, {NaOH}, is a ternary
compound.


Caustic \Caus"tic\, Caustical \Caus"tic*al\, a. [L. caustucs,
Ge. ?, fr. ? to burn. Cf. {Calm}, {Ink}.]
1. Capable of destroying the texture of anything or eating
away its substance by chemical action; burning; corrosive;
searing.

2. Severe; satirical; sharp; as, a caustic remark.

{Caustic curve} (Optics), a curve to which the ray of light,
reflected or refracted by another curve, are tangents, the
reflecting or refracting curve and the luminous point
being in one plane.

{Caustic lime}. See under {Lime}.

{Caustic potash}, {Caustic soda} (Chem.), the solid
hydroxides potash, {KOH}, and soda, {NaOH}, or solutions
of the same.

{Caustic silver}, nitrate of silver, lunar caustic.

{Caustic surface} (Optics), a surface to which rays reflected
or refracted by another surface are tangents. Caustic
curves and surfaces are called catacaustic when formed by
reflection, and diacaustic when formed by refraction.

Syn: Stinging; cutting; pungent; searching.