A. B. (Albert Benjamin) Prescott.

Qualitative chemical analysis; a guide in qualitative work, with data for analytical operations and laboratory methods online

. (page 32 of 57)
Online LibraryA. B. (Albert Benjamin) PrescottQualitative chemical analysis; a guide in qualitative work, with data for analytical operations and laboratory methods → online text (page 32 of 57)
Font size
QR-code for this ebook

of HNO 3 . Evaporate the nitrates to dryness, powder, digest
with alcohol,* filter and wash with alcohol (or digest and wash
with equal volumes of alcohol and ether.)

Residue: Sr(NO 3 ) 2 .
Precipitation by CaSO 4 in water
solution: flame test, etc.

Filtrate: Ca(NO 3 ) 2 .
Precipitation by H 2 SO 4 in alco-
hol solution, by (NH 4 ) 2 C 2 O 4 ,

Or, the alcoholic filtrate of SrCl 2 and CaCl 2 may be precipitated with (a
drop of) sulphuric acid, the precipitate filtered out and digested with
solution of (NH 4 ),S0 4 and a little NH 4 OH . Residue, SrS0 4 . Solution
contains CaS0 4 , precipitable by oxalates.

196. If the alkaline earth metals are present in the original material
as phosphates, or in mixtures such that the treatment for solution will
bring them in contact with phosphoric acid; the process of analysis- must
be modified. One of the methods given under analysis of third and fourth
group metals in presence of phosphate* (145 and//.) must be employed.

197. The presence of oxalates will also interfere, necessitating the
evaporation and ignition to decompose the oxalic acid (151).

* Instead of alcohol the residue of the nitrates may be boiled with amyl alcohol. Calcium
nitrate is dissolved making a complete separation from the strontium nitrate '188, 5c),


Potassium. K = ;J9.10. Caesium. Cs = 132.81.
Sodium. Na = 23.00. Rubidium. Rb = 85.45.
Ammonium. (NH 4 )'. Lithium. Li = 6.94.

198. The metals of ilio alkalis are highly combustible, oxidizing qnickly
in the air, displacing the hydrogen of water even more rapidly than zinc
or iron displaces the hydrogen of acids, and displacing non-alkali metals
from their oxides and salts. As elements they are very strong reducing
agents, while their compounds are very stable, and "not liable to either re-
duction or oxidation by ordinary means. The five metals, Cs , Rb , K ,
Na , Li , present a gradation of electro-positive or basic power, cesium
being strongest, and the others decreasing in the order of their atomic
weights, lithium decomposing water with less violence than the others.
Their specific gravities decrease,* their fusing points rise, and as carbon-
ates their solubilities lessen, in the same order. In solubility of the phos-
phate, also, lithium approaches the character of an alkaline earth (6).

Ammonium is the basal radical of ammonium salts, and as such has
many of the characteristics of an alkali metal. The water solution of the
gas ammonia, NH 3 (an anhydride), from analogy is supposed to contain
ammonium hydroxide, NH 4 OH, known as the volatile alkali. Potassium
and sodium hydroxides are the fixed alkalis in common use.

199. The alkalis are very soluble in water, and all the important salts
of the alkali metals (including NH 4 ) are soluble in water, not excepting their
carbonates, phosphates (except lithium), and silicates; while all other
metals form hydroxides or oxides, either insoluble or sparingly soluble, and
carbonates, phosphates, silicates, and certain other salts quite insoluble in

Their compounds being nearly all soluble, the alkali metals are not pre-
cipitated by ordinary reagents, and, with few exceptions, their salts do not
precipitate each other. In analysis, they are mostly separated from other
metals by non-precipitation.

200. In accordance with the insolubility in water of the non-alkali
hydroxides and oxides, the alkali hydroxides precipitate all non-alkali metals,
except that ammonium hydroxide does not precipitate barium, strontium,
and calcium. These precipitates are hydroxides, except those of mercury,
silver, and antimony. But certain of the non-alkali hydroxides and
oxides, though insoluble in water, dissolve in solutions of alkalis; hence,
when added in excess, the alkalis redissolve the precipitates they at first pro-
duce with salts of certain metals, viz. : the hydroxides of Pb , Sn , Sb (oxide),

* Except those of potassium (0,875) and sodium (0.9735).

228 POTASSIUM. 201.

Zn , Al, and Cr dissolve in the fixed alkalis; and oxide of Ag and hy-
droxides of Cu , Cd , Zn , Co , and Ni dissolve in the volatile alkali.

201. Solutions of the alkalis are caustic to the taste and touch, and
turn red litmus blue; also, the carbonates, acid carbonates, normal and
dibasic phosphates, and some other salts of the alkali metals, give the
" alkaline reaction " with test papers. Sodium nitrof erricyanide, with
hydrogen sulphide, gives a delicate reaction for the alkali hydroxides
(207, 66).

202. The hydroxides and normal carbonates of the alkali metals are not
decomposed by heat alone (as are those of other metals), and these metals
form the only acid carbonates obtained in the solid state.

203. The fixed alkalis, likewise many of their salts, melt on platinum
foil in the flame, and slowly vaporize at a bright red heat. All salts of
ammonium, by a careful evaporation of their solutions on platinum foil,
may be obtained in a solid residue, which rapidly vaporizes, wholly or
partly, below a red heat (distinction from fixed alkali metals).

204. The hydroxides of the fixed alkali metals, and those of their salts
most volatile at a red heat, preferably their chlorides, impart strongly
characteristic colors to a non-luminous flame, and give well-defined spectra
with the spectroscope.

205. Potassium. K = 39.10. Valence one.

1. Properties Specific gravity, 0.875 at 13 (Baumhauer, B., 1873, 6, 655).
Melting point, 62.3 (Cir. B. of S., 1915). Boiling point, 719 to 731 (Car-
nelley and Williams, B., 1879, 12, 1360); 667 (Perman, J. C., 1889, 55, 328).
Silver-white metal with a bluish tinge. At ordinary temperature of a. wax-like
consistency, ductile and malleable; at it is brittle. It is harder than Na
and is scratched by Li , Pb , Ca and Sr . The glowing vapor is a very beautiful
intense violet (Dudley, Am., 1892, 14, 185). It is next to caesium and rubidium,
the most electro-positive of all metals, remains unchanged in dry air, oxidizes
rapidly in moist air, and decomposes water with great violence, evolving
hydrogen, burning with a violet flame. At a red heat CO and C0 2 are
decomposed, at a white heat the reverse action takes place. Liquid chlorine
does not attack dry potassium (Gautier and Charpy, C. r., 1891, 113, 597). Acids
attack it violently, evolving hydrogen.

2. Occurrence. Very widely distributed as a portion of many silicates. In
sea water in small amount as KC1 . In numerous combinations in the large
salt deposits, especially at Stassfurt; e.g., carnallite, KCl.Mg-Cl, + 6H 2 O;
kainite, K 2 S0 4 .MgSO 4 .MgCl2 + 6H 2 , etc. As an important constituent of
many plants grape, potato, sugar-beet, tobacco, fumaria, rumex, oxalis, etc.

3. Preparation. (1) By reduction of the carbonate with carbon. (2) By
electrolysis of the hydroxide (Horning and Kasemeyer, B., 1889, 22, 277c;
Castner, B., 1892, 25, 179c). (3) By reduction of K 2 CO 3 or KOH with iron car-
bide: 6KOH + 2FeC 2 = 6K + 2Fe + 2CO + 2C0 2 + 3H, (Castner, C. N., 1886,
54, 218). (//) By reduction of the carbonate or hydroxide with Fe or Mg
(Winkler, B., 1890, 23, 44).

4. Oxides and Hydroxide. Potassium oande* K 2 , is prepared by carefully

* The existence of tfce oxides M',Q of K, Na and Jito is disputed (Erdmann apd Koetlmer, 4*
1896, 294, 55),

205, 65. POTASSIUM. 229

heating 1 potassium with the necessary amount of oxygen (air) (Kuhnemann,
C. C., 1863, 491); also by heating- K,O 4 with a mixture of K and Ag (Beketoff,
C. C., 1881, 643). It is a hard, gray mass, melting above a red heat. \Yater
changes it to KOH with generation of much heat. I'oldxxiuin lii/dro.ridc, KOH,
is formed by treating K or K 2 O with water; by boiling a solution of K,CO :!
with Ba , Sr or Ca oxides; by heating K,C0 3 with Fe.Og to a red heat and
decomposing the potassium ferrate with water (Ellershausen, C. C., 1891, (1),
1047; (2), 399). Pure water-free KOH is a white, hard, brittle mass, melting
at a red heat. It dissolves in water with generation of much heat. Potassium
supcro.t'idc, K._>O 4 , is formed when K is heated in contact with abundance of air
(Harcoiirt. ,/. (7., 1862, 14, 267); also by bringing K in contact with KNO 3
heated until it begins to evolve (liolton, C. A'., 1886, 53, 289). It is an amor-
phous powder of the color of lead chromate. Upon ignition in a silver dish
oxygen is evolved and K 2 O and AgoO formed (Harcourt, I. c.). Moist air or
water decomposes it with evolution of oxygen. It is a powerful oxidizing
agent, oxidizing S to Svi , P to PV , K , As , Sb , Sn , Zn , Cu , Fe , Ag and Pt
to the oxides (Bolton, I. c.' Brodie, Proc. Roy. &oc., 1863, 12, 209).

5. Solubilities. K and K 2 dissolve in water with violent action, forming
KOH , which reacts with all acids forming soluble salts. Potassium dissolves
in alcohol, forming potassium alcoholate and hydrogen.

Potassium platinum chloride, acid tartrate, silico-fluoride, picrate, phos-
phomolybdate, perchlorate, and chlorate are only sparingly soluble in
cold water, and nearly insoluble in alcohol. The carbonate and sulphate
are insoluble in alcohol. ,

6. Reactions, a. Potassium and sodium hydroxides are very strong
bases, fixed alkalis, and precipitate solutions of the salts of all the other
metals (except Cs , Rb , and Li), as oxides or hyHroxides. These precipi-
tates are quite insoluble in water, except the hydroxides of Ba , Sr , and
Ca . Excess of the reagent causes a resolution with the precipitates of
Pb, Sb, Sn, Al, Cr, and Zn , forming double oxides as, K 2 Pb0 2 , potas-
sium plumbite, etc. Potassium carbonate is deliquescent, strongly alkaline,
and precipitates solutions of the salts of the metals (except Cs , Rb , Na ,
and Li), forming normal carbonates with Ag , Hg', Cd , Fe", Mn , Ba , Sr ,
and Ca ; oxide with Sb ; hydroxide with Sn , Fe"', Al , Cr'" and Co'"; basic
salt with Hg", and a basic carbonate with the other metals.

&. - The potassium salts of HCN, H 4 Fe(CN) 6 , H 3 Fe(CN) 6 , and HCNS
find extended application in the detection and estimation of many of the
heavy metals.

Tartaric acid, H 2 C 4 H 4 6 , or more readily sodium hydrogen tartrate,
NaHC 4 H 4 6 , precipitates, from solutions sufficiently concentrated, potas-
sium hydrogen tartrate, KHC 4 H 4 , granular-crystalline. If the solution
be alkaline, acetic or tartaric acid should be added to strong acid reaction.
The test must be made in absence of non-alkali bases. The precipitate is
increased by agitation, and by addition of alcohol. It is dissolved by
fifteen parts of boiling water or eighty-nine parts water at 25, by mineral
acids, by solution of borax, and by alkalis, which form the more soluble
normal tartrate, K.,C 4 H 4 6 , but not by acetic acid, or at all by alcohol
of fifty per cent.

230 POTASSIUM. 205, 60.

Picric acid, C 6 H 2 (N0 2 ) 3 OH , or preferably its sodium salt, precipitates,
from solutions not very dilute, the yellow, crystalline potassium picrate,
C 6 H 2 (N0 2 ) 3 OK, soluble in 260 parts of water at 15 C. (Reichard,
Z. 40, 25), insoluble in alcohol, by help of which it is formed in dilute
solutions. The solution must be nearly neutral to avoid precipitation of
the slightly soluble picric acid (soluble in 160 parts water). The dried
precipitate detonates strongly when heated.

c. If a neutral solution of a potassium salt be added to a solution of cobaltic
nitrite,* a precipitate of the double salt potassium cobaltic nitrite, K 3 Co(NO 2 ) 6 ,
will be formed. In concentrated solutions the precipitate forms immediately,
dilute solutions should be allowed to stand for some time; sparingly soluble in
water, insoluble in alcohol and in a solution of potassium salts, hence the
precipitation is more valuable as a separation of cobalt from nickel than as a
test for potassium (132, 6c).

Potassium nitrate is not found abundantly in nature, but is formed by the
decomposition of nitrogenous organic substances in contact with potassium
salts, " saltpeter plantations "; or by treating a hot solution of NaN0 3 with
KC1 (Z)., 2, 2, 72). It finds extended application in the manufacture of gun-
powder, d. See 206, 6d.

e. Potassium sulphide may be taken as a type of the soluble sulphides
which precipitate solutions of the metals of the first four groups as
sulphides except: Hg' becomes HgS and Hg, Fe'" becomes FeS and S,
and Al and Cr form hydroxides. The sulphides of arsenic, antimony and
tin dissolve in an excess of the reagent, more rapidly if the alkali sulphide
contain an excess of sulphur. For the general action of H,S or soluble
sulphides as a reducing agent see the respective metals. Potassium sul-
phate is used to precipitate barium, strontium, and lead. It almost always
occurs in nature as double salt with magnesium, K 2 S0 4 .MgS0 4 .MgCl 2 -{-
6H 2 , kainite, and is used in the manufacture of KA1(S0 4 ) 2 , K 2 C0 3 and
KOH . As a type of a soluble sulphate it precipitates solutions of lead,
mercurosum, barium, strontium, and calcium; calcium and mercurosum

/. Potassium chloride precipitates the metals of the first group, acting
thus as a type of the soluble chlorides. It is much used with sodium
nitrate in the preparation of potassium nitrate for the manufacture of
gunpowder, in the preparation of K 2 C0 3 , KOH , and also as a fertilizer.
Potassium bromide as a type of the soluble bromides precipitates solutions
of Pb, Ag, and Hg (Hg" incompletely). Potassium iodide finds extended
use in analytical chemistry in that it forms many soluble double iodides;
it is also extensively used in medicine. As a typo of a soluble iodide it
precipitates solutions of the salts of Pb , Ag, Hg , and Cu'. Cu" salts
are precipitated as Cul with liberation of iodine. Fe"' salts are merely

* One cc. of cobaltous nitrate solution and three cc. of acetic acid are added to five cc. of a ten
per cent solution of sodium nitrite. This gives a yellowish solution having an odor of nitrous

205, 7. POTASSIUM. 231

reduced to Fe" salts with liberation of iodine. Arsenic acid is merely

reduced to arsenous acid with liberation of iodine.

Potassium chlorate is used as a source of oxygen and as an oxidizing agent
in acid solutions. Sodium perchlorate, NaClO 4 , precipitates from solutions of
potassium salts i>ot<ixxinin ftcn-hlonite, KC1O., , sparingly soluble in water and
almost insoluble in strong alcohol (Kreider, %. anory., 1895, 9, 342). Potassium
iodate is used as a reagent in the detection of barium as Ba(IO 8 )o . <j. The
oxides of iirxcuic act as acid anhydrides toward KOH and form stable soluble
potassium salts, arsenites and arsenates, which react with the salts of nearly
all the heavy metals, h. Potassium chromate and dichromate are both exten-
sively used as "reagents, especially in the analysis of Ag , Pb and Ba salts.

i. Fluosilicic acid,, H 2 SiF 6 , precipitates from a neutral or slightly
acid solution of potassium salts, potassium fluosilicate (silico-fluoride),
K,SiF c , soluble in 833.1 parts of water at 17.5; in 104.8 parts at 100;
and in 327 parts of 9.6 per cent HC1 at 14 (Stolba, J. pr., 1868, 103, 396\
The precipitate is white, very nearly transparent.

;'. Hydrochlorplatinic acid, H 2 PtCl G , added to neutral or acid solutions
not too dilute, precipitates potassium clilorplatinate, K 2 PtCl , crystalline,
yellow. Non-alkali bases also precipitate this reagent, and if present must be
removed before this test. The precipitate is soluble in 19 parts of boiling
water, or 111 parts of water at 10. Minute proportions are detected by
evaporating the solution with the reagent nearly to dryness, on the water-
bath, and then dissolving in alcohol; the yellow crystalline precipitate,
octahedral, remains undissolved, and may be identified under the micro-

k. An alcoholic solution of BiCl 3 in excess of Na^Os gives a yellow precipitate
with solutions of potassium salts (Pauly, C. C., 1887, 553). 1. Gold chloride added
to sodium and potassium chloride forms chloraurates, e.g., KAuCl, -f !'H 2 O .' If
these salts are dried at 100 to 110 to remove water and acids, the sodium salt is
soluble in ether (separation from potassium) (Fasbender, C. C., 1894, 1, 409).

7. Ignition. Ignited potassium hydroxide or potassium carbonate is a
valuable desiccating agent for use in desiccators or in liquids. A mixture
of molecular proportions of K 2 CO a and Na 2 C0 3 melts at a lower tempera-
ture than either of the constituents, and is frequently employed in fusion
for the transposition of insoluble metallic compounds : BaS0 4 -f- K>C0 3 =
BaC0 3 -f K 2 S0 4 .

Potassium compounds color the flame violet. A little of the solid
substance, or residue by evaporation, moistened with hydrochloric acid,
is brought on a platinum wire into a non-luminous flame. The wire
should be previously washed with HC1, and held in the flame to insure
the absence of potassium. The presence of very small quantities of
sodium enables its yellow flame completely to obscure the violet of potas-
sium; but owing to the greater volatility of the latter metal, flashes of
violet are sometimes seen on the first introduction of the wire, or at the
border of the flame, or in its base, even when enough sodium is present
to conceal the violet at full heat. The interposition of a blue glass, or

232 SODIUM. 205, 8.

to conceal the violet at full heat. The interposition of a blue glass, or
prism filled with indigo solution, sufficiently thick, entirely cuts off the
yellow light of sodium, and enables the potassium name to be seen. The
red rays of the lithium flame are also intercepted by the blue glass or
indigo prism,, a thicker stratum being required than for sodium. It
organic substances are present, giving luminosity to the flame,, they must
be removed by ignition. Certain non-alkali bases interfere with the
examination. Silicates may be fused with pure gypsum, giving vapor of
potassium sulphate. Bloxam (J. C., 1865, 18, "229) recommends to fuse
insoluble alkali compounds with a mixture of sulphur, one part, and
barium nitrate, six parts; cool, dissolve in w^ater, remove the barium with
NH 4 OH and (NH 4 ) 2 C0 3 and test for the alkalis as usual.

The volatile potassium compounds, when placed in the flame, give a
widely-extended continuous spectrum, containing two characteristic lines;
one line, K , situated in the outermost red, and a second line, K /?, far in
the violet rays at the other end of the spectrum.

8. Detection. Potassium is usually identified by the violet blue color
which most of its salts impart to the Bunsen flame (7). Sodium inter-
feres but the intervention of a cobalt glass (132, 7) or a solution of
indigo cuts out the yellow color of the sodium flame and allows the violet
of the potassium to be seen. Some of the heavy metals interfere, hence
the test should be made after the removal of the heavy metals (211
and 212).

Potassium may be precipitated as the platinichloride (6/); as the per-
chlorate (6/); as the silico-fluoride (6i); as the acid tartrate (66); etc.
Certain of these reactions are much used for the quantitative estimation
(9) of potassium but are seldom used for its detection qualitatively.

9. Estimation. (1) Potassium is converted into the sulphate or phosphate
and weighed as such. (2) It is precipitated and weighed as the double chloride
with platinum. (3) If present as KOH or K 2 CO 3 it is titrated with standard
acid (Kippenberger, Z. angew., 1894, 495). (4) It is precipitated with H 2 SiF 6
and strong alcohol. (5) Indirectly when mixed with sodium, by converting
into the chlorides and weighing as such; then determining the amount of
chlorine and calculating the relative amounts of the alkalis. (6) It is pre-
cipitated as the bitartrate in presence of alcohol and, after nitration and
solution in hot water, titrated with deci-normal KOH. (7) By precipitation as
the perchlorate, KC1O 4 (Wense, Z. angew., 1892, 233; Caspari, Z. angew., 1893, 68).

10. Oxidation. Potassium is a very powerful reducing agent, its affinity
for oxygen at temperatures not too high is greater than that of any other
element except Cs and Rb . For oxidizing action of K 2 4 see 4.

206. Sodium. Na = 23.00. Valence one.

1. Properties. Specific gravity, 0.9735 at 13.5 (Baumhauer, B., 1873, 6,
665); 0.7414 at the boiling point (Ramsay, B., 1880, 13, 2145). Melting point,
97.5 (Cir. B. of S., 1915). Boiling point, 742 (Perman, C. N., 1889, 59, 237)


206, 6d. SODIUM. PHARMACY 233

A silver-white metal with a strong- metallic lustre. At ordinary temperatures
it is softer than Li or Pb, and can be pressed together between the fingers;
at 20 it is quite hard; at very ductile. It oxidizes rapidly in moist air
and must be kept under benzol or kerosene. It decomposes water violently
even at ordinary temperatures, evolving- hydrogen, which frequently ignites
from the heat of the reaction: 2Na + 2H 2 O = 2NaOH + H 2 . It burns, when
heated to a red heat, with a yellow flame. Pure dry Na is scarcely at all
attacked by dry HC1 (Cohen, C. N., 1886, 54, 17).

2. Occurrence. Never occurs free in nature, but in its various combinations
one of the most widely diffused metals. There is no mineral known in which
its presence has not been detected. It occurs in all waters mostly as the
chloride from traces in drinking waters to a nearly saturated solution in some
mineral waters and in the sea water. It is found in enormous deposits as rock
salt, NaCI; as Chili saltpeter, NaNO 3 ; in lesser quantities as carbonate, borate,
sulphate, etc.

3. Preparation. (1) By igniting- the carbonate or hydroxide with carbon;
(2) by igniting- the hydroxide with metallic iron; (3) by electrolysis of the
hydroxide; (4) by gently heating the carbonate with Mg- .

4. Oxides and Hydroxides. Sodium oxide, Na.O , is formed by burning
sodium in oxygen or in air and heating again with Na to decompose the Na 2 O 2
(205, 4, footnote). Sodium hydroxide, NaOH , is formed by dissolving the
metal or the oxide in water (Rosenfeld, J. pr., 1893, (2), 48, 599); by treating
a solution of sodium carbonate with lime; by fusion of NaN0 3 with CaC0 3 ,
CaO and Na,CO 3 are formed and the mass is then exhausted with water: by
igniting Na 2 C0 3 with Fe 2 O 3 , forming sodium ferrate, which is then decom-
posed with hot water into NaOH and Fe(OH) 3 (Solvay, C. C., 1887, 829). It is
a white, opaque, brittle crj-stalline body, melting under a red heat. The
fused mass has a sp. gr. of 2.13 (Filhol, A. Ch., 1847, (3), 21, 415). It has a very
powerful affinity for w r ater, gradually absorbing water from CaCl 2 (Mtiller-
Erzbach, B., 1878, 11, 409). It is soluble in about 0.47 part of water according
to Bineau (C. r., 1855, 41, 509).

Sodium peroxide, Na,0 2 , is formed by heating sodium in CO,, free air or
oxygen (Prud'homme, C. C., 1893, (1), 199). It reacts as H 2 2 , partly reducing
and partly oxidizing. It may be fused without decomposition. Water decom-
poses it partially into NaOH and H,O 2 .

5. Solubilities. Sodium and sodium oxide dissolve in water, forming
the hydroxide, the former with evolution of hydrogen. In acids the
corresponding sodium salts are formed, all soluble in water except sodium
pyroantimonate, which is almost insoluble in water, and the fluosilicate
sparingly soluble.

The nitrate and chlorate are deliquescent. The carbonate (10 aq), sul-
phate (10 aq), sulphite (8 aq), phosphate (12 aq), and the acetate (3 aq) are

6. Keactions. a. As reagents sodium hydroxide and carbonates act in
all respects like the corresponding potassium compounds, which see.

ft. By the greater solubility of the picrate and acid tnrlrafc of sodium, that
metal is separated from potassium (205, 6ft). c. Sodium nitrate occurs in
nature in large quantities as Chili saltpeter, used as a fertilizer, for the manu-
facture of nitric acid, with KC1 for making KNO 3 , etc.

d. Sodium phosphate, Na.HP0 4 , is much used as a reagent in the
precipitation and estimation of Pb , Mn , Ba , Sr , Ca , and Mg . The
phosphates of all metals except the alkalis are insoluble in water (lithium
phosphate is only sparingly soluble (210, 5c), soluble in acids). Solu-

234 SODIUM. 206, 6e.

tions of alkali phosphates precipitate solutions of all other metallic salts
as phosphates (secondary, tertiary or basic) except: HgCl 2 precipitates as
a basic chloride (58, 6d), and antimony as oxide or oxychloride (70, 6d).

e, f, g, 1i. As reagents the sodium salts react, similar to the corresponding-
potassium salts, which see. i. Sodium, fluosilicate is soluble in 153.3 parts
H 2 O at 17.5 and in 40.66 parts at 100 (Stolba, ., 1872, 11, 199); hence is not

Online LibraryA. B. (Albert Benjamin) PrescottQualitative chemical analysis; a guide in qualitative work, with data for analytical operations and laboratory methods → online text (page 32 of 57)