soda ash Anhydrous *sodium carbonate, Na 2 CO 3 .
soda lime A mixed hydroxide of
sodium and calcium made by slaking
lime with caustic soda solution (to
give NaOH + Ca(OH) 2 ) and recovering
greyish white granules by evaporation. The material is produced largely
for industrial adsorption of carbon
dioxide and water, but also Ünds
some applications in pollution and
efÛuent control. It is also used as a
laboratory drying agent.
sodamide See sodium amide.
Soddy, Frederick (1877–1956)
British chemist, who worked with
Ernest *Rutherford in Canada and
William *Ramsay in London before
Ünally settling in Oxford in 1919. His
announcement in 1913 of the existence of *isotopes won him the 1921
Nobel Prize for physics.
sodium Symbol Na. A soft silvery
reactive element belonging to group
1 (formerly IA) of the periodic table
(see alkali metals); a.n. 11; r.a.m.
22.9898; r.d. 0.97; m.p. 97.8°C; b.p.
882–889°C. Sodium occurs as the
chloride in sea water and in the mineral halite. It is extracted by electrolysis in a Downs cell. The metal is
used as a reducing agent in certain
reactions and liquid sodium is also a
coolant in nuclear reactors. Chemically, it is highly reactive, oxidizing
in air and reacting violently with
water (it is kept under oil). It dissolves in liquid ammonia to form
blue solutions containing solvated
electrons. Sodium is a major *essential element required by living organisms. The element was Ürst isolated
by Humphry Davy in 1807.
A
• Information from the WebElements site
sodium acetate See sodium
ethanoate.
sodium aluminate A white solid,
NaA1O 2 or Na 2 Al 2 O 4 , which is insoluble in ethanol and soluble in
water giving strongly alkaline solutions; m.p. 1800°C. It is manufactured by heating bauxite with
sodium carbonate and extracting
the residue with water, or it may be
prepared in the laboratory by adding
excess aluminium to hot concentrated sodium hydroxide. In solution the ion Al(OH) 4
– predominates.
Sodium aluminate is used as a
mordant, in the production of zeolites, in efÛuent treatment, in glass
manufacture, and in cleansing compounds.
sodium amide (sodamide) A white
crystalline powder, NaNH 2 , which decomposes in water and in warm
ethanol, and has an odour of ammonia; m.p. 210°C; b.p. 400°C. It is produced by passing dry ammonia over
metallic sodium at 350°C. It reacts
with red-hot carbon to give sodium
cyanide and with nitrogen(I) oxide to
give sodium azide.
sodium azide A white or colourless crystalline solid, NaN 3 , soluble in
water and slightly soluble in alcohol;
hexagonal; r.d. 1.846; decomposes on
heating. It is made by the action of
nitrogen(I) oxide on hot sodamide
(NaNH 2 ) and is used as an organic
reagent and in the manufacture of
detonators.
sodium benzenecarboxylate
(sodium benzoate) An either colourless crystalline or white amorphous
powder, C 6 H 5 COONa, soluble in
water and slightly soluble in ethanol.
It is made by the reaction of sodium
hydroxide with benzoic acid and is
used in the dyestuffs industry and as
a food preservative. It was formerly
used as an antiseptic.
sodium benzoate See sodium benzenecarboxylate.
487
sodium benzoate
s
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soda lime A mixed hydroxide of
sodium and calcium made by slaking
lime with caustic soda solution (to
give NaOH + Ca(OH) 2 ) and recovering
greyish white granules by evaporation. The material is produced largely
for industrial adsorption of carbon
dioxide and water, but also Ünds
some applications in pollution and
efÛuent control. It is also used as a
laboratory drying agent.
sodamide See sodium amide.
Soddy, Frederick (1877–1956)
British chemist, who worked with
Ernest *Rutherford in Canada and
William *Ramsay in London before
Ünally settling in Oxford in 1919. His
announcement in 1913 of the existence of *isotopes won him the 1921
Nobel Prize for physics.
sodium Symbol Na. A soft silvery
reactive element belonging to group
1 (formerly IA) of the periodic table
(see alkali metals); a.n. 11; r.a.m.
22.9898; r.d. 0.97; m.p. 97.8°C; b.p.
882–889°C. Sodium occurs as the
chloride in sea water and in the mineral halite. It is extracted by electrolysis in a Downs cell. The metal is
used as a reducing agent in certain
reactions and liquid sodium is also a
coolant in nuclear reactors. Chemically, it is highly reactive, oxidizing
in air and reacting violently with
water (it is kept under oil). It dissolves in liquid ammonia to form
blue solutions containing solvated
electrons. Sodium is a major *essential element required by living organisms. The element was Ürst isolated
by Humphry Davy in 1807.
A
• Information from the WebElements site
sodium acetate See sodium
ethanoate.
sodium aluminate A white solid,
NaA1O 2 or Na 2 Al 2 O 4 , which is insoluble in ethanol and soluble in
water giving strongly alkaline solutions; m.p. 1800°C. It is manufactured by heating bauxite with
sodium carbonate and extracting
the residue with water, or it may be
prepared in the laboratory by adding
excess aluminium to hot concentrated sodium hydroxide. In solution the ion Al(OH) 4
– predominates.
Sodium aluminate is used as a
mordant, in the production of zeolites, in efÛuent treatment, in glass
manufacture, and in cleansing compounds.
sodium amide (sodamide) A white
crystalline powder, NaNH 2 , which decomposes in water and in warm
ethanol, and has an odour of ammonia; m.p. 210°C; b.p. 400°C. It is produced by passing dry ammonia over
metallic sodium at 350°C. It reacts
with red-hot carbon to give sodium
cyanide and with nitrogen(I) oxide to
give sodium azide.
sodium azide A white or colourless crystalline solid, NaN 3 , soluble in
water and slightly soluble in alcohol;
hexagonal; r.d. 1.846; decomposes on
heating. It is made by the action of
nitrogen(I) oxide on hot sodamide
(NaNH 2 ) and is used as an organic
reagent and in the manufacture of
detonators.
sodium benzenecarboxylate
(sodium benzoate) An either colourless crystalline or white amorphous
powder, C 6 H 5 COONa, soluble in
water and slightly soluble in ethanol.
It is made by the reaction of sodium
hydroxide with benzoic acid and is
used in the dyestuffs industry and as
a food preservative. It was formerly
used as an antiseptic.
sodium benzoate See sodium benzenecarboxylate.
487
sodium benzoate
s
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