Encyclopaedia Britannica, or, a Dictionary of arts, sciences, and miscellaneous literature : enlarged and improved. Illustrated with nearly six hundred engravings > Volume 5, BUR-CHI

6-2 CHEMISTRY.
Zihc, 8tc. ^)f hycfcbgen gas. Tlie metal is oxidated, and then
t~*~v diffolves in the acid j but the properties of this fait are
little known.
15. Acetate of Zinc.
Zinc, &c.
1777
Prepara¬
tion.
7. Borate of Zinc.
Boracic acid combines with the oxide of zinc, by
adding the borate of potafh or foda to the folution of
zinc in nitric or muriatic acid. Xhis fait is infoluble
in water.
8.
Phofphate of Zinc.
Phofphorie acid diluted with water, a£ls upon zinc
with the evolution of hydrogen gas, owing to the de-
compofition of water. A white powder is depofited,
which is phofphate of zinc. By expoling phofphoric
glafs and zinc to a ftrong heat, a phofphuret of zinc
is formed, by the decompofition of the acid.
Acetic acid diffolves zinc, and the folution by eva-prep'^_
poration cryftallizes in the form of rhomboidal ortionand
hexagonal plates. This fait has a bitter metallic properties,
tafte, is not altered by expofure to the air, and is fo-
luble in water. It burns with a blue flame when
thrown on burning coals. When diftilled, it yields
water, an inflammable liquid, and fome oil. At the
end of the procefs, when the fait is completely de-
compofed, the oxide of zinc is fublimed, which being
brought in contaft with a candle, burns with a fine
blue flame. The refiduum is in the ftate of pyropho-
rus, but it has little combuftibility.
16. Oxalate of Zinci
1778
Prepara¬
tion.
9. Carbonate of Zinc.
Zinc reduced to a fine powder, and added, to liquid
carbonic acid, is oxidated and copioufly diffolved in
the acid, at the end of 24 hours. This folution, ex-
pofed to the air, is covered with a pellicle of car¬
bonate of zinc of different colours. The carbonate of
zinc is found native, and has been diftinguiftred by the
name of calamine^ thus confounding it with the oxide
of zinc. Carbonate of zinc, according to the analyfis
of Bergman, is compofed of
Oxalic acid a£hs upon zinc with effervefcence, and
the evolution of hydrogen gas. Water is decompof-
ed, and as the zinc is oxidated, it combines with the
acid, forming an oxalate of zinc. It is in the ftate of
white powder, of an acrid tafte, and but little foluble
in water.
17. Tartrate of Zinc.
Tartaric acid combines with zinc with effervefcence,
and the evolution of hydrogen gas. The properties of
this fait have not been examined.
18. Citrate of Zinc.
Acid 28
Oxide 66
Water 6
100
10. Arfeniate of Zinc.
When arfenic acid is added to zinc, it produces an
effervefcence, with the evolution of hydrogen gas,
holding arfenic in folution. A black powder is de¬
pofited, which is metallic arfenic. In this procefs,
the zinc decompofes part of the water, and combines
with its oxygen, and at the fame time deprives the
arfenic acid of its oxygen, by which it is reduced to
the metallic ftate. The arfeniate of zinc may be ob¬
tained by adding a folution of an alkaline arfeniate
to a folution of the fulphate of zinc. A white pre¬
cipitate is formed, which is the arfeniate of zinc. It
is infoluble in water.
XI. Tungftate of Zinc.
12. Molybdate of Zinc.
Thefe falls may be formed by a fimilar procefs. A
white powder is obtained, which is infoluble in water.
13. Chromate of Zinc.
This fait is obtained by combining an alkaline chro¬
mate with a folution of zinc in nitric acid. A precipi-
tate is formed of an orange red colour, which is chro¬
mate of zinc.
14. Coiumbate of Zinc.
Unknown.
Citric acid a£ts upon zinc with effervefcence and
the evolution of hydrogen gas. At the end of 24
hours the aftion ceafes, and the liquid depofits on the
fides of the veffel and on its furface, fmall, brilliant
cryftals in the form of plates, which are infoluble in
water. The citrate of zinc has an aftringent, metallic
tafte. It is compofed of equal parts of acid and of ‘
oxide of zinc.
19. Malate of Zinc.
Malic acid diffblves zinc, and, by evaporating the
folution, cryftals may be obtained.
20. Benzoate of Zinc.
Benzoic acid readily diffolves zinc, and by evapo¬
ration the folution affords needle-ftiaped cryftals. The
benzoate of zinc is foluble in water and alcohol. When
it is expofed to heat, the acid is fublimed.
21. Succinate of Zinc.
Zinc is diffolved in fuccinic acid with effervefcenee.
By evaporation the folution affords flender, foliated
cryftals.
22. La&ate of Zinc.
Zinc is foluble in laftic acid with effervefcence, and
by evaporating the folution, the fait may be obtained
cryftallized.
II. Adlion of Alkalies, &c. on Zinc.
1786
I. When zinc is immerfed in a folution of potafh Fixed alfca-
or foda, it is tarnifhed, and becomes black, and when lies,
it is boiled in the folution, hydrogen gas is evolved.
The folution affumes a dirty-yellow colour, from which
an oxide of zinc may be precipitated by acids.
2. Ammonia'